4. Forces are called concurrent when their lines of action meet in
(a) one point      
(b) two points
(c) plane
(d) perpendicular planes
(e) different planes.
Ans: a

5. Forces are called coplanar when all of them acting on body lie in
(a) one point      
(b) one plane
(c) different planes
(d) perpendicular planes
(e) different points.
Ans: b

6. A force acting on a body may
(a) introduce internal stresses
(b) balance the other forces acting on it
(c) retard its motion
(d) change its motion
(e) all of the above.
Ans: e

7. Which is the correct statement about law of polygon of forces ?
(a) if any number of forces acting at a point can be represented by the sides
of a polygon taken in order, then the forces are in equilibrium
(b) if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium
(c) if a polygon representing forces acting at a point is closed then forces are in equilibrium
(d) if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, then the forces are in equilibrium
(e) none of the above.
Ans: d

8. Effect of a force on a body depends upon
(a) magnitude
(b) direction
(c) position or line of action
(d) all of the above
(e) none of the above.
Ans: d

9. If a number of forces act simultaneously on a particle, it is possible
(a) not a replace them by a single force
(b) to replace them by a single force
(c) to replace them by a single force through C.G.
(d) to replace them by a couple
(e) to replace them by a couple and a force.
Ans: b

11. A force is completely defined when we specify
(a) magnitude
(b) direction
(c) point of application
(d) all of the above
(e) none of the above.
Ans: d

12. If two equal forces of magnitude P act at an angle 9°, their resultant will be
(a) P/2 cos 9/2
(b) IP sin 9/2
(c) 2P tan 9/2
(d) IP cos 9/2
(e) Psin 9/2.
Ans: d

13. The algebraic sum of the resolved parts of a number of forces in a given direction is equal to the resolved part of their resultant in the same direction. This is as per the principle of
(a) forces
(b) independence of forces
(c) dependence of forces
(d) balance of force
(e) resolution of forces.
Ans: e

14. The resolved part of the resultant of two forces inclined at an angle 9 in a given direction is equal to
(a) the algebraic sum of the resolved parts of the forces in the given direction
(b) the sum of the resolved parts of the forces in the given direction
(c) the difference of the forces multiplied by the cosine of 9
(d) the sum of the forces multiplied by the sine of 9
(e) the sum of the forces multiplied by the tangent of 9.
Ans: a

15. Which of the following do not have identical dimensions ?
(a) Momentum and impulse
(b) Torque and energy
(c) Torque and work
(d) Kinetic energy and potential energy
(e) Moment of a force and angular momentum.
Ans: e

16. Which of the following is not the unit of distance ?
(a) angstrom
(b) light year
(c) micron
(d) millimetre
(e) milestone.
Ans: e

17. Which of the following is not the unit of power ?
(a) kW (kilowatt)
(b) hp (horse power)
(c) kcal/sec
(d) kg m/sec
(e) kcal/kg sec.
Ans: e

18. Which of the following is not the unit of work, energy and heat ?
(a) kcal
(b) kg m
(c) kWhr
(d) hp
(e) hp hr.
Ans: d

19. Which of the following is not the unit of pressure ?
(a) kg/cm
(b) ata
(c) atmosphere    
(d) mm of wcl
(e) newton.
Ans: e

20. The weight of a body is due to
(a) centripetal force of earth
(b) gravitational pull exerted by the earth
(c) forces experienced by body in atmosphere
(d) force of attraction experienced by particles
(e) gravitational force of attraction towards the center of the earth.
Ans: e

21. The forces, which meet at one point, but their lines of action do not lie in a plane, are called
(a) coplanar non-concurrent forces
(b) non-coplanar concurrent forces
(c) non-coplanar non-concurrent forces
(d) intersecting forces
(e) none of the above.
Ans: b

22. When trying to turn a key into a lock, following is applied
(a) coplanar force
(b) non-coplanar forces
(c) lever
(d) moment
(e) couple.
Ans: e

23. Which of the following is not a scalar quantity
(a) time
(b) mass
(c) volume
(d) density
(e) acceleration.
Ans: e

24. According to principle of transmissibility of forces, the effect of a force upon a body is
(a) maximum when it acts at the center of gravity of a body
(b) different at different points in its line of action
(c) the same at every point in its line of action
(d) minimum when it acts at the C.G. of the body
(e) none of the above.
Ans: c

25. Which of the following is a vector quantity
(a) energy
(b) mass
(c) momentum    
(d) angle
(e) speed.
Ans: c

26. The magnitude of two forces, which when acting at right angle produce resultant force  of VlOkg and when acting at 60° produce resultant of Vl3 kg. These forces are
(a) 2 and V6
(b) 3 and 1 kg
(c) V5 and V5
(d) 2 and 5
(e) none of the above.
Ans: c

27. A number of forces acting at a point will be in equilibrium if
(a) their total sum is zero
(b) two resolved parts in two directions at right angles are equal
(c) sum of resolved parts in any two per-pendicular directions are both zero
(d) all of them are inclined equally
(e) none of the above.
Ans: c

28. Two non-collinear parallel equal forces acting in opposite direction
(a) balance each other
(b) constitute a moment
(c) constitute a couple
(d) constitute a moment of couple
(e) constitute a resultant couple.
Ans: c

29. According to principle of moments
(a) if a system of coplanar forces is in equilibrium, then their algebraic sum is zero
(b) if a system of coplanar forces is in equilibrium, then the algebraic sum of their moments about any point in their plane is zero
(c) the algebraic sum of the moments of any two forces about any point is equal to moment of theiwesultant about the same point
(d) positive and negative couples can be balanced
(e) none of the above.
Ans: b

30. Which of the following is not a vector quantity
(a) weight
(b) velocity
(c) acceleration  
(d) force
(e) moment.
Ans: a

Engineering Mechanics MCQ  : Part 1 | Part 2 | Part 3 | Part 4