If the work done by the string on block A is W. Then work done by the string on the block B will be

                              

(1)  -W

(2)  $-\frac{\mathrm{W}}{2}$

(3)  2W

(4)  Zero

If the pulley system with the ideal mechanical advantage of 4 requires a force of 15 N to lift a load of 45 N, then the efficiency of the pulley is

(1)  25%

(2)  30%

(3)  40%

(4)  75%

Choose incorrect statement about the oblique collision of two bodies.

(1)  The momentum of each body is conserved along the tangent.

(2)  The momentum of the system is conserved.

(3)  The momentum of each body is conserved along common normal.

(4)  Coefficient of restitution is considered along the common normal.

A small block of mass m is pulled by a light rope on a quarter circular track, having radius R. If the force applied on the rope is F always directed horizontally, then the work done by the force till the block reaches from A to B is:

(1)  FR

(2)  $\mathrm{FR}\sqrt{2}$

(3)  $\mathrm{F}2\mathrm{\pi R}$

(4)  Zero

A stone of mass m is thrown from the earth's surface at an angle $\mathrm{\alpha }$ to the horizontal with an initial velocity ${\mathrm{v}}_0$. Ignoring the air drag, the power developed by gravitational force t second after the beginning of motion is:

(1)  $\mathrm{mg}\left(\mathrm{gt} - {\mathrm{v}}_0\mathrm{sin\alpha }\right)$

(2)  ${\mathrm{mgv}}_0\mathrm{sin\alpha }·\mathrm{t}$

(3)  $\mathrm{mg}\left(\mathrm{g} - \mathrm{vsin\alpha }·\mathrm{t}\right)$

(4)  Zero

An ideal horizontal spring has been compressed by two masses of 1 kg and 4 kg at its ends placed on a frictionless table. The stored energy is 40 joule. If the spring is released, the lighter mass will acquire a speed of:

(1)  2 m/s

(2)  4 m/s

(3)  8 m/s

(4)  16 m/s

A car of mass 100 kg and traveling at 20 m/s collides with a truck weighing 1 tonne traveling at 9 km/h in the same direction. The car bounces back at a speed of 5 m/s. The speed of the truck after the impact will be:

1.  11.5 m/s

2.  5 m/s

3.  18 m/s

4.  12 m/s

If work done by the string on block A is W, shown in the given arrangement, then the work done by the string on block B is

1.  -W

2.  $-\frac{2\mathrm{W}}{3}$

3.  $\frac{3\mathrm{W}}{2}$

4.  $\frac{2\mathrm{W}}{3}$

Which of the following remains unchanged (for the system) during an inelastic collision?

The position (in meter) of a particle of mass 1 kg confined to move along the y-axis varies with time (in second) as y= ${\mathrm{t}}^2$ - 4t+ 5. The work done by all the forces acting on the particle during t = 0 to t = 4 s is

(1)  8 J

(2)  16 J

(3)  32 J

(4)  Zero