1. A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act
Correct : D. upward at its upper end
2. The forces which do not meet at one point and their lines of action do not lie on the same plane are known as
Correct : D. none of these
3. The linear acceleration (a) of a body rotating along a circular path of radius (r) with an angular acceleration of ? rad / s2, is
Correct : B. a = ?.r
4. The velocity ratio in case of an inclined plane inclined at angle ? to the horizontal and weight being pulled up the inclined plane by vertical effort is
Correct : A. sin ?
5. A body of mass m moving with a constant velocity v strikes another body of same mass m moving with same velocity but in opposite direction. The common velocity of both the bodies after collision is
Correct : B. 2 v
6. When a body of mass m attains a velocity v from rest in time t, then the kinetic energy of translation is
Correct : C. 0.5 mv2
7. Whenever a force acts on a body and the body undergoes a displacement, then
Correct : A. work is said to be done
8. The maximum displacement of a body, from its mean position is called amplitude.
Correct : A. Right
9. The unit of power in S.I. units is
Correct : C. watt
10. The moment of inertia of a solid cylinder of mass m, radius r and length l about the longitudenal axis or polar axis is
Correct : A. mr2 / 2
11. When the spring of a watch is wound, it will possess
Correct : A. strain energy
12. The path of the projectile is a parabola.
Correct : A. True
13. The wheels of a moving car possess
Correct : D. kinetic energy of translation and rotation both
14. Frequency of vibrations means the number of cycles per second.
Correct : A. Yes
15. A resultant force is a single force which produces the same effect as produced by all the given forces acting on a body
Correct : A. TRUE
16. The maximum mechanical advantage of a lifting machine is
Correct : C. 1 / m
17. In a wormed geared pully block, if the number of teeth one the worm wheel is doubled, then its velocity ratio is also doubled.
Correct : A. True
18. The moment of inertia of a thin rod of mass m and length l, about an axis through its centre of gravity and perpendicular to its length is
Correct : D. ml2 / 12
19. Coplaner non-concurrent forces are those forces which
Correct : B. do not meet
20. The linear velocity of a body rotating at ? rad / s along a circular path of radius r is given by
Correct : B. ?.r
21. The acceleration of a particle moving with simple harmonic motion is
Correct : A. zero
22. When a train is rounding a curve, the side thrust on the wheel flanges is prevented by raising the outer edge of the rail.
Correct : A. Yes
23. In collision of elastic bodies, the coefficient of restitution is the ratio of the relative velocity after impact to the relative velocity before impact.
Correct : A. True
24. The rate of change of displacement of a body is called
Correct : A. velocity
25. The maximum frictional force, which comes into play, when a body just begins to slide over the surface of the other body, is known as
Correct : C. limiting friction
26. The negative acceleration is called retardation.
Correct : A. True
27. The velocity ratio for the second system of pulleys is n.
Correct : A. True
28. The angle between two forces when the resultant is maximum and minimum respectively are
Correct : A. 0? and 180?
29. The angular velocity (in rad / s) of a body rotating at N revolutions per minute is
Correct : C. 2? N / 60
30. If P is the force acting on the body, m is the mass of the body and a is the acceleration of the body, then according to Newton's second law of motion,
Correct : B. P - m.a = 0
31. Coplaner concurrent forces are those forces which
Correct : C. meet at one point and their lines of action also lie on the same plane
32. The time of flight of a projectile on downward inclined plane depends upon
Correct : C. both (a) and (b)
33. Concurrent forces are those forces whose lines of action
Correct : B. meet at one point
34. During elastic impact, the relative velocity of the two bodies after impact is
Correct : B. equal and opposite to
35. Coefficient of friction depends upon
Correct : B. nature of surface only
36. Work done is said to be zero, when
Correct : C. either (a) or (b)
37. The moment of inertia of a square of side (a) about an axis through its centre of gravity is
Correct : C. a4/12
38. When a particle moves along a straight path, there will be centripetal acceleration as well as tangential acceleration.
Correct : B. Wrong
39. The motion of the body from one extremity to the other is known as a beat.
Correct : A. Agree
40. The force which acts along the radius of a circle and directed towards the centre of the circle is known as centripetal force.
Correct : A. True
41. The centre of gravity of a quadrant of a circle lies along its central radius (r) at a distance of
Correct : B. 0.6 r
42. A body is said to move or vibrate with simple harmonic motion if its acceleration is directed towards the mean position.
Correct : A. True
43. The unit of energy in S.I. units is
Correct : D. joule
44. The slope on the road surface generally provided on the curves is known as
Correct : C. angle of banking
45. Two balls of equal mass and of perfectly elastic material are lying on the floor. One of the ball with velocity v is made to struck the second ball. Both the balls after impact will move with a velocity
Correct : B. v / 2
46. According to the law of moments, if a number of coplaner forces acting on a particle are in equilibrium, then
Correct : C. the algebraic sum of their moments about any point in their plane is zero
47. A force while acting on a body may
Correct : D. all of these
48. For a self locking machine, the efficiency must be
Correct : B. less than 50%
49. The maximum acceleration of a particle moving with simple harmonic motion is