Block A moves on the smooth surface and collides with the block B at rest. The maximum energy stored in the spring will be

                    

1.  $\frac{1}{8}{\mathrm{mv}}^2$

2.  $\frac{1}{4}{\mathrm{mv}}^2$

3.  $\frac{1}{3}{\mathrm{mv}}^2$

4.  $\frac{1}{2}{\mathrm{mv}}^2$

An object of mass 2 kg falls from rest through a vertical distance 10 m and acquires a velocity of 10 m/s. The work done by the resistive force of air on the object is (g = 10 $\mathrm{m}/{\mathrm{s}}^2$)

(1)  200 J

(2)  -200 J

(3)  150 J

(4)  -100J

A body of \(10\) kg is subjected to a force as shown in the figure. The block moves along a straight line under the influence of this force. The change in kinetic energy when the body moves from \(x=0\) to \(x=4\) m will be:

1. \(15\) J
2. \(12.5\) J
3. \(17.5\) J
4. \(19.2\) J

A constant horizontal force is applied on a block kept at rest on a smooth horizontal surface. Its power \((P)\) versus time \((t)\) graph is best shown by:

1.		2.
3.		4.

A block slides down an inclined plane of inclination 30° with a constant velocity. It then projected up with an initial speed of 6 m/s, the distance moved by it on the inclined before coming to rest is

(1)  1.5 m

(2)  1.8 m

(3)  2.0 m

(4)  2.4 m

The potential energy of a particle of mass 0.5 kg moving along x axis is given by

U = 2x (x - 3). The speed of the particle is maximum at

(1)  x = 1 m

(2)  x = 1.5 m

(3)  X = 2 m

(4)  x = 3 m

A ball strikes the floor at an angle of ${45}^{\mathrm{o}}$ with vertical and rebounds of an angle of 60° with the vertical. Assuming the contact to be smooth the coefficient of restitution is

1.  1

2.  $\frac{1}{\sqrt{2}}$

3.  $\frac{1}{3}$

4.  $\frac{1}{\sqrt{3}}$

Work energy theorem is valid in

(1)  Only inertial frame of reference

(2)  The only non-inertial frame of reference

(3)  Both inertial and non-inertial frame of reference

(4)  Does not depend on any frame of reference

A block of mass m is projected with speed v along the rough surface of an inclined plane of height h. If block comes to rest at the top of the surface, then work done by friction force is

1.  $-\frac{1}{2}{\mathrm{mv}}^2$

2.  $\mathrm{m}\left[\mathrm{gh} - \frac{1}{2}{\mathrm{v}}^2\right]$

3.  -mgh

4.  $\mathrm{m}\left[\mathrm{gh} + \frac{1}{2}{\mathrm{v}}^2\right]$

A body of mass m moving with speed v collides head-on elastically with another identical body at rest. The percentage loss in kinetic energy of the first body will be: