# Engineering Mechanics – Section 1

11. A smooth cylinder lying on its convex surface remains in __________ equilibrium.

A. stable
B. unstable
C. neutral

12. The coefficient of friction is the ratio of the limiting friction to the normal reaction between the two bodies.

A. Yes
B. No

13. Moment of inertia of a circular section about an axis perpendicular to the section is

A. πd3/16
B. πd3/32
C. πd4/32
D. πd4/64

14. The time of flight (t) of a projectile on an upward inclined plane is(where u = Velocity of projection, α = Angle of projection, and β = Inclination of the plane with the horizontal.) 15. The unit of angular acceleration is

A. N-m
B. m/s
C. m/s2

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

A. bh3/4
B. bh3/8
C. bh3/12
D. bh3/36

17. If the masses of both the bodies, as shown in the below figure, are reduced to 50 percent, then tension in the string will be A. same
B. half
C. double

18. Which of the following is an equation of linear motion? (where, u and v = Initial and final velocity of the body, a = Acceleration of the body, and s = Displacement of the body in time t seconds.)

A. v = u + a.t
B. s = u.t + 1/2 a.t2
C. v2 = u2+2a.s
D. all of these

Correct Answer: D. all of these

19. If a number of forces are acting at a point, their resultant will be inclined at an angle θ with the horizontal, such that

A. tan θ = ∑H/∑V
B. tan θ = ∑V/∑H
C. tan θ = ∑Vx∑H
D. Correct Answer: B. tan θ = ∑V/∑H

20. The above figure shows the two equal forces at right angles acting at a point. The value of force R acting along their bisector and in opposite direction is

A. P/2
B. 2P
C. D. Correct Answer: C 