The C.G. of a solid hemisphere lies on the central radius 3r_________________?

A. At distance — from the plane base 3r
B. At distance — from the plane base 3r
C. At distance — from the plane base 3r
D. At distance — from the plane base or

A flywheel on a motor goes from rest to 1000 rpm in 6 sec. The number of revolutions made is nearly equal to_________________?

A. 25
B. 50
C. 100
D. 250

If n = number of members andy = number of joints, then for a perfect frame, n =________________?

A. J-2
B. 2j-l
C. 2/-3
C. 3/-2

The necessary condition for forces to be in equilibrium is that these should be_____________________?

A. Coplanar
B. Meet at one point ;
C. Both a. and b. above
D. All be equal

The maximum frictional force which comes into play when a body just begins to slide over another surface is called________________?

A. Limiting friction
B. Sliding friction
C. Rolling friction
D. Kinematic friction

A single force and a couple acting in the same plane upon a rigid body_________________?

A. Balance each other
B. Cannot balance each other
C. Produce moment of a couple
D. Are equivalent

A particle inside a hollow sphere of radius r, having coefficient of friction -rr can rest upto height of___________________?

A. R/2
B. R/a
C. R/%
D. 0.134 r

The effort required to lift a load W on a screw jack with helix angle a and angle of friction

A. Wtan(a + )
B. Wtan(a-)
C. Wcos(a + )
D. Wsin(a + )

Coulomb friction is the friction between_____________________?

A. Bodies having relative motion
B. Two dry surfaces
C. Two lubricated surfaces
D. Solids and liquids

A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is__________________?

A. 0°
B. 30°
C. 45°
D. 60°