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Multiple choice question for engineering

Set 1

1. __________ is a structure made of slender members which are joined together at their end points.
a) Truss
b) Beam
c) Pillar
d) Support

View Answer

Answer: a [Reason:] The truss is a structure made of slender members which are joined together at their end points. They can be of wooden or steel. But most probably they are made from stainless steel. As they need to support the loadings in various climates.

2. _________ trusses lie on a plane.
a) Planar
b) 2D
c) Linear
d) 3D

View Answer

Answer: a [Reason:] The planar trusses lie on a plane. Like for e.g. the trusses in the bridges. These trusses are the main supports of the bridge. They are extended straight vertical and are strong enough to resist various changes in the weather.

3. In a roof supporting truss the load is transmitted when ________
a) First to the truss then the joints through purlins
b) First to the purlins then the joints through trusses
c) First to the truss then the purlins through joints
d) First to the joints then the trusses through purlins

View Answer

Answer: a [Reason:] The roof load is transmitted to the truss first. It is then transmitted to the joints. This transmission of the force or the load from trusses to the joints is achieved by the purlins. Thus the distribution of the load.

4. As the loading is acting in the two dimensions, that is in a single plane. Thus the calculations involved in the trusses are in 2D.
a) True
b) False

View Answer

Answer: a [Reason:] The loading is acting in a plane. Thus the calculations are done in 2D only. As the equations for 3D are different. Although the use of vectors can make our task easy but still 2D calculations are done for the trusses, as they are acting in a same plane.

5. In case of bridge the load is transferred when __________
a) Stringers > floor beams > joints
b) Floor beams > stringers > joints
c) Joints > floor beams > stringers
d) Stringers > joints > floor beams

View Answer

Answer: a [Reason:] The bridge load is transmitted to the stringers first. It is then transmitted to the floor beams. The load from beams is then transmitted to the joints. Thus the transmission of the load of the bridge.

6. As the loading in bridge different from the simple trusses the calculations involved in the bridges are all 2D calculations.
a) True
b) False

View Answer

Answer: b [Reason:] The loading in the bridge is acting in a plane. Thus the calculations are done in 2D only. As the equations for 3D are different. Although the use of vectors can make our task easy but still 2D calculations are done for the trusses, as they are acting in a same plane. But the thing is that the loading in bridge and trusses are same.

7. When the bridges are extended over long routes or distance then _________
a) A rocker or a roller is used at the joints
b) They are not extended to such a long distance
c) The bridges are painted
d) The roads are made narrow

View Answer

Answer: a [Reason:] When the bridges are extended over long routes or distance then a rocker or a roller is used at the joints. This allows the bridge joints to move around. That is when the temperature is raised. The elongations and the contractions of the joints part are not much affected if the rollers and rockers are used.

8. Find the force in the member RP of the frame shown below.

engineering-mechanics-questions-answers-simple-trusses-1-q8
a) 707.1N
b) 500N
c) 505N
d) 784N

View Answer

Answer: b [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

9. To design the trusses which of the following rules is followed?
a) All the loads are applied by the use of cables
b) The loads ae applied at the joints
c) All the loads are not applied at the joints
d) The loads are not applied at all to the joints

View Answer

Answer: b [Reason:] The set of rules which are used to design the trusses are having various rules. To them one is that the loads are applied at the joints. This is done with the neglecting of the weight of the trusses section.

10. The rules which are used to design the trusses are having various rules. Of them one is that the smooth pins are not used to join the members.
a) Statement is correct
b) Statement is incorrect
c) Statement is incorrect because there are no rules
d) Statement is incorrect as the rolling pins are used

View Answer

Answer: a [Reason:] The set of rules used to design the trusses are having various rules. Of them one is that the smooth pins are used to join the members. The joint are generally formed by welding the materials at the ends of the trusses. Which gives strength to the design.

11. Find the force in the member RQ of the frame shown below.

engineering-mechanics-questions-answers-simple-trusses-1-q11

a) 566N
b) 400N
c) 773N
d) 1090N

View Answer

Answer: d [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

12. Find the force in the member QS of the frame shown below.

engineering-mechanics-questions-answers-simple-trusses-1-q12

a) 566N
b) 400N
c) 773N
d) 1090N

View Answer

Answer: a [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

13. A _________ truss is in triangular section.
a) Equilateral
b) Simple
c) Complex
d) Lateral

View Answer

Answer: b [Reason:] A simple truss in the shape of a triangle. It is the equilateral triangle. That is the angle between the legs are 60. This means the load is divided according and are equal in all the legs of the truss. Hence the simple truss.

14. Find the force in the member PQ of the frame shown below.

engineering-mechanics-questions-answers-simple-trusses-1-q14

a) 566N
b) 546N
c) 773N
d) 1090N

View Answer

Answer: b [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

15. Which of the following is correct?
a) To know the direction of the unknown force we take assumption of it
b) The direction of the unknown force is known to us already
c) The direction of the unknown can’t be determined
d) The direction of the unknown is of no use, it is not founded

View Answer

Answer: a [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly.

Set 2

1. The basic type of motion of a body is translation motion only.
a) True
b) False

View Answer

Answer: b [Reason:] The basic types of the motion of the body are translation and rotational. In which translation means the motion is a straight motion while the in the rotational motion the body is moving of the body along the axis.

2. Find the total resultant force acting horizontally in the given figure below, consisting of a beam with various sections?

engineering-mechanics-questions-answers-simplification-force-couple-system-1-q2

a) 350N
b) 50N
c) 250N
d) 300N

View Answer

Answer: d [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

3. Principle of transmissibility is
a) It states that the force acting on the body is a sliding vector
b) It states that the force acting on the body is a rolling vector
c) It states that the force acting on the body is a wedging vector
d) It states that the force acting on the body is a unit vector

View Answer

Answer: a [Reason:] Principle of transmissibility states that the force acting on the body is a sliding vector. That is it can be applied at any point of the body. It will give the same effect as if applied at any point other that the specific point. Thus the answer.

4. Coplanar forces are not easily simplified in the simplification of the force and couple system.
a) True
b) False

View Answer

Answer: b [Reason:] The coplanar forces can be easily simplified in the simplification of the force and couple system. This is not only for the coplanar system of the forces, but for any of the dimension vector. Which means the answer is false.

5. What will be the total resultant force acting vertically in the figure given below consisting of a beam with various sections?

engineering-mechanics-questions-answers-simplification-force-couple-system-1-q5

a) 350N
b) 50N
c) 250N
d) 300N

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

6. The simplification of the couple is done on the basis of the ______________
a) The clockwise of the anti-clockwise rotation sign convention
b) The simplification is not possible
c) The couple is a vector and thus can’t be simplified
d) The couple is a scalar and can’t be simplified

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

7. The simplification of the forces on the axis is done as______________
a) A particular system of rule is followed
b) No simplification of the forces is possible
c) The forces are already simplified and don’t need simplification
d) The forces are very tentative quantity on terms of simplification and hence no simplification possible

View Answer

Answer: a [Reason:] A particular system of the rules is followed that is if the upward direction is taken as positive then the downward direction is taken as negative. This is same as done with the couple in the 2D. That is the forces can be easily simplified. If taken in the vector form then the task is even easier.

8. Find the total resultant force acting horizontally in the given figure consisting of a beam of ‘L’ shape?

engineering-mechanics-questions-answers-simplification-force-couple-system-1-q8

a) 60N
b) 605N
c) 0N
d) 6N

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

9. The couple is a scalar quantity and the force is vector quantity and hence only force can be simplified as __________
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: a [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

10. The force and the couple can’t be simplified together as one is the cause and the other is the effect.
a) The statement is correct and the reason given is also correct
b) The statement is wrong but the reason given is also correct
c) The statement is wrong and the reason given is also wrong
d) The statement is correct but the reason given is also wrong

View Answer

Answer: c [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

11. The main moto of the simplification is to ______________
a) To reduce the calculation
b) To add the forces with the couples and take out the total
c) To subtract the forces with the couples and take out the total
d) To multiply the forces with the couples and take out the total

View Answer

Answer: a [Reason:] The main moto of the simplification is to reduce the calculation. The forces are simplified and the couples too are simplified. This gives us the total force and the total moment acting on the body. This gives us a single value of the respective thing and hence reduces the labour.

12. Find the total resultant force acting vertically in the given figure below consisting of a beam of ‘L’ shape.

engineering-mechanics-questions-answers-simplification-force-couple-system-1-q12

a) 180N
b) 18N
c) 10N
d) 100N

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

13. The couple is simplified easily by the help of right hand rule. But the forces simplification is not possible as there is no such system of rules so that the forces can be simplified.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: c [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D. Forces are simplified on the basis of the algebra.

14. The couple moment and the force is divided to get the distance of the axis from the point of action of the force.
a) True
b) False

View Answer

Answer: a [Reason:] The couple is the cross product of the force and the perpendicular distance between the forces. And if the division of the both is done than the resulting quantity is the distance only. But care must be taken that the product is the cross product and hence sine angle must be divided too to get the distance.

15. Find the total resultant moment acting vertically in the given figure below consisting of a beam of ‘L’ shape.

engineering-mechanics-questions-answers-simplification-force-couple-system-1-q15

a) 640Nm
b) 60Nm
c) 40Nm
d) 400Nm

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

Set 3

1. __________ is a structure made of slender members which are joined together at their end points.
a) Space Truss
b) Pillar
c) Beam
d) Support

View Answer

Answer: a [Reason:] The space truss is a structure made of slender members which are joined together at their end points. They can be of wooden or steel. But most probably they are made from stainless steel. As they need to support the loadings in various climates.

2. As the loading is acting in the three dimensions, that is in a multi planes. Thus the calculations involved in the trusses are in 3D.
a) True
b) False

View Answer

Answer: a [Reason:] The loading is acting in a plane. Thus the calculations are done in 2D only. As the equations for 3D are different. Although the use of vectors can make our task easy but still 2D calculations are done for the trusses, as they are acting in a same plane.

3. Which of the following is correct for space trusses?
a) To know the direction of the unknown force we take assumption of it
b) The direction of the unknown force is known to us already
c) The direction of the unknown can’t be determined
d) The direction of the unknown is of no use, it is not founded

View Answer

Answer: a [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly.

4. Find the force in the member RQ.

engineering-mechanics-questions-answers-space-trusses-q4

a) 750N
b) 450N
c) 250N
d) 200N

View Answer

Answer: b [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

5. As the loading in bridge different from the simple trusses the calculations involved in the bridges are all 2D calculations.
a) True
b) False

View Answer

Answer: b [Reason:] The loading in the bridge is acting in a plane. Thus the calculations are done in 2D only. As the equations for 3D are different. Although the use of vectors can make our task easy but still 2D calculations are done for the trusses, as they are acting in a same plane. But the thing is that the loading in bridge and trusses are same.

6. In case of bridge the load is transferred as:
a) Stringers > floor beams > joints
b) Floor beams > stringers > joints
c) Joints > floor beams > stringers
d) Stringers > joints > floor beams

View Answer

Answer: a [Reason:] The bridge load is transmitted to the stringers first. It is then transmitted to the floor beams. The load from beams is then transmitted to the joints. Thus the transmission of the load of the bridge.

7. To design the space trusses which of the following rules is followed?
a) All the loads are applied by the use of cables
b) The loads ae applied at the joints
c) All the loads are not applied at the joints
d) The loads are not applied at all to the joints

View Answer

Answer: b [Reason:] The set of rules which are used to design the trusses are having various rules. To them one is that the loads are applied at the joints. This is done with the neglecting of the weight of the trusses section.

8. The rules which are used to design the space trusses are having various rules. Of them one is that the smooth pins are not used to join the members.
a) Statement is correct
b) Statement is incorrect
c) Statement is incorrect because there are no rules
d) Statement is incorrect as the rolling pins are used

View Answer

Answer: a [Reason:] The set of rules used to design the trusses are having various rules. Of them one is that the smooth pins are used to join the members. The joint are generally formed by welding the materials at the ends of the trusses. Which gives strength to the design.

9. In a roof supporting space truss the load is transmitted as:
a) First to the truss then the joints through purlins
b) First to the purlins then the joints through trusses
c) First to the truss then the purlins through joints
d) First to the joints then the trusses through purlins

View Answer

Answer: a [Reason:] The roof load is transmitted to the truss first. It is then transmitted to the joints. This transmission of the force or the load from trusses to the joints is achieved by the purlins. Thus the distribution of the load.

10. The free body diagram of which part of the section of the space truss is made to make use of method of joints?
a) Joints
b) Truss
c) The whole structure
d) The combination of joint and the whole structure

View Answer

Answer: a [Reason:] The free body diagram of joints part of the section of the truss is made to make use of method of joints. Various equations of equilibrium are made to do the calculations. The net force acting on the vertical direction is made zero. Also horizontal direction forces are made to be zero.

11. Find the force in the member RQ of the frame shown below.

engineering-mechanics-questions-answers-space-trusses-q11

a) 566N
b) 400N
c) 773N
d) 1090N

View Answer

Answer: d [Reason:] The direction of the unknown is not known to us. To know the direction of the unknown force we take assumption of it. That is we assume that the particular direction might be the direction of the force and then we do the calculations accordingly. And then we apply the equilibrium equations to the joints.

12. We use the method of joint to find the forces acting over the joints in the space trusses. In this we start from the joint having at least one known force and at the most two unknown forces.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: d [Reason:] This makes the calculations easy. Also for the solving of any equation one requires equal number of variables as that of equal number of equation. So to do the calculations easily the above mentioned conditions are followed.

13. As space trusses are used in bridges. When the bridges are extended over long routes or distance then:
a) A rocker or a roller is used at the joints
b) They are not extended to such a long distance
c) The bridges are painted
d) The roads are made narrow

View Answer

Answer: a [Reason:] When the bridges are extended over long routes or distance then a rocker or a roller is used at the joints. This allows the bridge joints to move around. That is when the temperature is raised. The elongations and the contractions of the joints part are not much affected if the rollers and rockers are used.

14. What is after taking the assumption of the direction of the force in space trusses, the direction comes opposite?
a) The assumption made was wrong and the question can’t be solved further
b) The assumptions are not to be taken
c) The direction is in the opposite sense, and hence the direction is known to us
d) The direction will be already given to us, no need of assuming

View Answer

Answer: c [Reason:] The direction is comes opposite, means that the assumption was wrong. But that doesn’t means that the question can’t be solved further. One needs to change the sign of the direction and the question is solved. Thus the calculations of the force direction.

15. _________ trusses lie on a 3D volume.
a) Planar
b) 2D
c) Linear
d) 3D

View Answer

Answer: d [Reason:] The planar trusses lie on a plane while the space truss in 3D volume. Like for e.g. the trusses in the bridges. These trusses are the main supports of the bridge. They are extended straight vertical and are strong enough to resist various changes in the weather.

Set 4

1. The main condition for the stability of equilibrium configuration is that the distance between various particles of the body does change.
a) True
b) False

View Answer

Answer: b [Reason:] The main condition for the rigid body is that the distance between various particles of the body does not change. If the distance does change the body is not to be called as rigid. Thus the fix distance of the particles is very much required for the equilibrium of the rigid body.

2. Determine the vertical components of the reaction on the beam caused by the pin at Q.

engineering-mechanics-questions-answers-stability-equilibrium-configurations-q2

a) 286N
b) 68N
c) 28N
d) 288N

View Answer

Answer: a [Reason:] The summation of the forces needs to be zero. So does the summation of the moments need to zero. But talking about the angles, they not needed to zero. But the forces which are acting at particular angles, must needed to be equal to zero. The basic need of the forces to make the body in equilibrium.

3. Which of the following is correct for stability of equilibrium configuration?
a) The application of the conditions of the equilibrium of the body is valid only in the 2D
b) The application of the conditions of the equilibrium of the body is valid only in the 3D
c) The application of the conditions of the equilibrium of the body is valid only in the 1D
d) The application of the conditions of the equilibrium of the body is valid throughout

View Answer

Answer: d [Reason:] The application of the conditions of the equilibrium of the body is valid throughout. This means that the conditions are irrespective of the dimensions. The conditions are the basic rules that defines the equilibrium of the body and thus are applicable in any dimension of the real axis.

4. For stability of equilibrium configuration the net force acting on the body is zero.
a) True
b) False

View Answer

Answer: a [Reason:] The equilibrium is only attained if the net force on the body tends to be equal to zero. Thus the forces cancels out. If this happens there is no motion of the body along any direction and hence the body is said to be in equilibrium. The body here is a rigid body.

5. For stability of equilibrium configuration the net moment acting on the body by various forces is zero.
a) True
b) False

View Answer

Answer: a [Reason:] The equilibrium is only attained if the net moment on the body tends to be equal to zero. Thus the moments caused by different forces cancels out. If this happens there is no motion of the body along any direction and hence the body is said to be in equilibrium. The body here is a rigid body.

6. The net force of the body is zero that means the force are not being applied to the body at all and hence the body has achieved stability.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: c [Reason:] The net force of the body is zero that doesn’t means that the force are not being applied to the body at all and hence the body is in equilibrium. The equilibrium is only attained if the net force on the body tends to be equal to zero. Thus the forces cancels out. If this happens there is no motion of the body along any direction and hence the body is said to be in equilibrium.

7. Which of the following needs to zero for the stability of equilibrium configuration?
a) ∑F=0, ∑M=0 and ∑θ = 0
b) ∑F=0, ∑M≠0 and ∑θ = 0
c) ∑F≠0, ∑M=0 and ∑θ = 0
d) ∑F=0, ∑M=0 and ∑θ≠0

View Answer

Answer: d [Reason:] The summation of the forces needs to be zero. So does the summation of the moments need to zero. But talking about the angles, they not needed to zero. But the forces which are acting at particular angles, must needed to be equal to zero. The basic need of the forces to make the body in equilibrium.

8. Determine the horizontal components of the reaction on the beam caused by the pin at Q. The force 60N is multiplied by 10 and then is applied.

engineering-mechanics-questions-answers-stability-equilibrium-configurations-q8

a) 0N
b) 445N
c) 45N
d) 40N

View Answer

Answer: a [Reason:] The summation of the forces needs to be zero. So does the summation of the moments need to zero. But talking about the angles, they not needed to zero. But the forces which are acting at particular angles, must needed to.

9. Free body diagrams doesn’t play any role in making the calculations on the conditions of stability of equilibrium configuration.
a) True
b) False

View Answer

Answer: b [Reason:] The free body diagrams does play an important role in the formation of the conditions of the equilibrium of the rigid body. As the net forces are zero, the fbd helps us to take the measure of the same. That is to see whether the summation is really zero or not.

10. The net moment of the body is zero that means the distance between the force and the rotational axis is zero thus the stability of equilibrium configuration.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: c [Reason:] The net moment of the body is zero that doesn’t means that the distance between the force and the rotational axis is zero. This means moments caused by different forces cancels out. If this happens there is no motion of the body along any direction and hence the body is said to be in equilibrium.

11. If the resolved force for the stability of equilibrium configuration or the force which you get as the answer after solving the question is negative, then what does this implies?
a) The force is in the reverse direction w.r.t the direction set in the free body diagram
b) The force is not in the reverse direction w.r.t the direction set in the free body diagram
c) The force component is not possible
d) The force is possible, but in the direction perpendicular to the resultant force

View Answer

Answer: a [Reason:] The negative sign implies things in the opposite manner. If the force is coming negative this doesn’t means that it is impossible. But it means that the force is in the opposite direction w.r.t the direction set by you in the free body diagram.

12. If the body is in stability of equilibrium configuration, but it having a rotational curled ray shown in the free body diagram then:
a) The diagram is wrong
b) Such rotations can’t be shown in the fbds(free body diagrams)
c) The ray shown may be correct, but the body is not said to be in equilibrium
d) The body is said to be in equilibrium only, as the other forces will cancel out that rotation

View Answer

Answer: d [Reason:] The body having equilibrium will not rotate at any cost. Yes, the diagram may contain the rotational array showing the couple being acted over the structure. But the thing is that the forces, i.e. the other forces which are outside the dependency of this rotation will cancel out this rotation and thus the body is in equilibrium.

13. If five forces are acting on the single particle and having an angle of 72˚ between each and are collinear, then:
a) The net force acting on the body is zero and it is stable
b) The net force acting on the body is horizontal
c) The net force acting on the body is vertical
d) The net force acting on the body is at an angle of 45

View Answer

Answer: a [Reason:] The net force acting on the body is zero. This means that the forces cancel out. This means that the body is in equilibrium and doesn’t need any of the external force to make itself in the equilibrium.

14. For the conditions of the stability of equilibrium configuration of the body, i.e. the body only the external forces defines the equilibrium. Because the internal forces cancels out so not to be considered.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: c [Reason:] The application of the internal forces does affect the conditions of the equilibrium of the body. Not only the external but the internal forces that are developed by the sake of external forces does develop a tending effect on the equilibrium of the body. Thus the internal forces doesn’t cancels out.

15. We need to apply vector math sometimes in the calculation of stability of equilibrium configurations. So the coordinate of the Force vector AB is A (2, 0, 2) and B (-2, 3.46, 3). It has a magnitude of 750N. Which is the best Cartesian representation of the vector AB?
a) -557i + 482j + 139k N
b) -557i – 482j + 139k N
c) -557i + 482j – 139k N
d) 557i – 482j – 139k N

View Answer

Answer: a [Reason:] First try to make the unit vector of AB. Then you will get the Cartesian form of unit vector, after that just multiply 750 scalar quantity with it. Which means you are first taking out the desired direction and then multiplying the scalar to get the desired vector in desired direction.

Set 5

1. What is a collinear system of forces?
a) The force system having all the forces parallel to each other
b) The force system having all the forces perpendicular to each other
c) The force system having all the forces emerging from a single point
d) Forces cannot form a collinear system of forces, it is not possible

View Answer

Answer: c [Reason:] The force system having all the forces emerging from a point is called the collinear system of force. This is a type of system of the force, which is easy in the simplification. This is because as the forces are the vector quantity, the vector math is applied and the simplification is done.

2. Find the total resultant force acting in the given figure consisting of a beam with various sections.
engineering-mechanics-questions-answers-test-q2
a) 350N
b) 461N
c) 250N
d) 300N

View Answer

Answer: b [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. After this the forces are a determined and are added vetorially to get the resultant force.

3. In the collinear force system a net force is being made after all the simplification done on all the forces.
a) True
b) False

View Answer

Answer: a [Reason:] The answer is obvious yes. As the simplification means addition and the subtraction of the forces. This results in the simplification of the forces and thus gives us a single force. It is in a particular direction and hence the statement is true.

4. Just like the collinear forces there are collinear couple and the net moment is taken out from it.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: c [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

5. Just like the collinear force system there is a system of the parallel forces.
a) True
b) False

View Answer

Answer: a [Reason:] There is a system so called the parallel system of the forces. This is another type of the forces. The simplification of this type of the forces is also very easy. This means that the forces in a certain direction is taken as positive and in the other direction is negative and hence the simplification is done.

6. Find the total resultant moment acting in the given figure consisting of a beam with various sections.

engineering-mechanics-questions-answers-simplification-force-couple-system-2-q6

a) 37.5Nm
b) 7.5Nm
c) 79.5Nm
d) 370.5Nm

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. If the couple is a vector it can be easily simplified by taking the components.

7. The system of the collinear and the parallel force are simplified as ______________
a) The simplified collinear force system gives us a net force and the parallel force system gives us a simplified force, and then we add it vectorially
b) Such simplification is not possible
c) The simplification is usually done by not considering the directions of the both
d) The simplification is done by considering the rotations only

View Answer

Answer: a [Reason:] The simplification is easy. The simplified force system gives us a net force and the parallel force system gives us a simplified force, and then we add it vectorially. Thus the vector addition at the last can be easily done and thus both can be simplified.

8. The couple and the other two force systems can be easily simplified.
a) Statement is wrong
b) Statement is right
c) Statement is right if we remove ‘couple’ part
d) Statement is right if we remove ‘force’ part

View Answer

Answer: b [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

9. The resultant force is equal to the _______ of all the forces.
a) Sum
b) Product
c) Subtraction
d) Division

View Answer

Answer: a [Reason:] As the simplification means addition and the subtraction of the forces. This results in the simplification of the forces and thus gives us a single force. It is in a particular direction. But if one is considering the direction with the magnitude of the force, we can say that the resultant is the sum of all the forces.

10. The couple is simplified easily by the help of left hand rule. But the forces simplification is not possible as there is no such system of rules so that the forces can be simplified.
a) The first part of the statement is false and other part is true
b) The first part of the statement is false and other part is false too
c) The first part of the statement is true and other part is false
d) The first part of the statement is true and other part is true too

View Answer

Answer: a [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D. Forces are simplified on the basis of the algebra.

11. The forces of the parallel system and the couple can’t be simplified together as one is the cause and the other is the effect.
a) The statement is correct and the reason given is also correct
b) The statement is wrong but the reason given is also correct
c) The statement is wrong and the reason given is also wrong
d) The statement is correct but the reason given is also wrong

View Answer

Answer: c [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

12. The forces of the collinear system and the couple can’t be simplified together as one is the cause and the other is the effect.
a) The statement is correct and the reason given is also correct
b) The statement is wrong but the reason given is also correct
c) The statement is wrong and the reason given is also wrong
d) The statement is correct but the reason given is also wrong

View Answer

Answer: c [Reason:] Both of them are vector quantities. And both of them can be easily simplified. If taken in the vector form then the task is even easier. Thus it is not necessary for the force or the couple to be vector only, even if the magnitude is taken, the simplification is done in the 2D.

13. Find the angle between the horizontal and vertical forces acting in the given figure consisting of a beam with various sections.

engineering-mechanics-questions-answers-simplification-force-couple-system-2-q13

a) 49.4˚
b) 9.4˚
c) 4.4˚
d) 40.4˚

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. As soon as the horizontal and the vertical forces are determined we can get the angle between them. This can be done by using the tangent trigonometry function.

14. Find the total resultant moment acting in the given figure consisting of a beam with various sections.

engineering-mechanics-questions-answers-simplification-force-couple-system-2-q14

a) 210Nm
b) 10Nm
c) 20Nm
d) 102Nm

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. As soon as the horizontal and the vertical forces are determined we can get the angle between them. This can be done by using the tangent trigonometry function.

15. Find the total resultant force acting in the given figure consisting of a beam with various sections.

engineering-mechanics-questions-answers-simplification-force-couple-system-2-q15

a) 157N
n) 175N
c) 15N
d) 17N

View Answer

Answer: a [Reason:] The couple is simplified by taking the direction of the rotation of the body as positive or negative. That is if the clockwise direction is positive then the anti-clockwise direction is taken as negative. After this the forces are a determined and are added vetorially to get the resultant force.