The effort required to lift a load W on a screw jack with helix angle a and angle of friction <j) is equal to_________________?

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

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

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

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

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

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

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

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

Which of the following is not the unit of energy________________?

A. Kg m
B. Kcal
C. Wattr
D. Watt hours

A sample of metal weighs 219 gms in air, 180 gms in water, 120 gms in an unknown fluid. Then which is correct statement about density of metal________________?

A. Density of metal can’t be determined
B. Metal is twice as dense as water
C. Metal will float in water
D. Metal is twice as dense as unknown fluid

A body moves, from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly________________?

A. 38 m
B. 62.5 m
C. 96 m
D. 124 m