31. The center of gravity of a quadrant of a circle lies along its central radius (r) at a distance of

A. 0.5r
B. 0.6r
C. 0.7r
D. 0.8r

32. The horizontal range of a projectile (R) is given by

A. R = u² cos2α/g
B. R = u² sin2α/g
C. R = u² cosα/g
D. R = u² sinα/g

33. Which of the following are vector quantities?

A. Angular displacement
B. Angular velocity
C. Angular acceleration
D. all of these

34. The maximum mechanical advantage of a lifting machine is

A. 1 + m
B. 1 – m
C. 1 / m
D. m

35. A machine having an efficiency greater than 50%, is known as

A. reversible machine
B. non-reversible machine
C. neither reversible nor non-reversible machine
D. ideal machine

36. The impact between two lead spheres is approximately equal to an __________ impact.

A. elastic
B. inelastic

37. Moment of inertia of a triangular section of the base (b) and height (h) about an axis passing through its vertex and parallel to the base, is __________ than that passing through its C.G. and parallel to the base.

A. nine times
B. six times
C. four times
D. two times

38. If a body is thrown upwards, then the gravitational acceleration is taken as zero.

A. Correct
B. Incorrect

39. An ideal machine is one whose efficiency is

A. between 60 and 70 %
B. between 70 and 80%
C. between 80 and 90%
D. 100%

40. The energy possessed by a body, for doing work by virtue of its position, is called

A. potential energy
B. kinetic energy
C. electrical energy
D. chemical energy