A moving block having mass \(m\) collides with another stationary block having a mass of \(4m.\) The lighter block comes to rest after the collision. When the initial velocity of the lighter block is \(v,\) then the value of the coefficient of restitution \((e)\) will be:
1. \(0.5\)
2. \(0.25\)
3. \(0.8\)
4. \(0.4\)

A body initially at rest and sliding along a frictionless track from a height \(\mathrm{h}\) (as shown in the figure) just completes a vertical circle of diameter \(\mathrm{AB=D}.\) The height \(\mathrm{h}\) is equal to:
      

1. $\frac{3}{2}D$

2. \(D\)

3. $\frac{7}{4}D$

4. $\frac{5}{4}D$

Consider a drop of rainwater having a mass of 1gm falling from a height of 1 km. It hits the ground with a speed of 50 m/s. Take 'g' constant with a value 10 m/s². The work done by the
(i) gravitational force and the
(ii) resistive force of air is:

1. (i) 1.25 J (ii) -8.25 J

2. (i) 100 J (ii) 8.75 J

3. (i) 10 J (ii) -8.75 J

4. (i) -10 J (ii) -8.75 J

Two identical balls A and B having velocities of 0.5 m/s and -0.3 m/s respectively collide elastically in one dimension. The velocities of B and A after the collision respectively will be 

(1) -0.5 m/s and 0.3 m/s 

(2) 0.5 m/s and -0.3 m/s 

(3) -0.3 m/s and 0.5 m/s 

(4) 0.3 m/s and 0.5 m/s 

A body of mass 1 kg begins to move under the action of a time dependent force \(F = 2 t\) \(\hat{i} + 3 t^{2}\ \hat{j}\) N, where \(\hat{i}\) and \(\hat{j}\) are unit vectors along X and Y axis, What power will be developed by the force at the time (t) ?

(a) \(\left(2 t^{2} + 4 t^{4}\right) W\)         

(b) \(\left(2 t^{3} + 3 t^{4}\right) W\)

(c) \(\left(2 t^{3} + 3 t^{5}\right) W\)         

(d) \(\left(2 t + 3 t^{3}\right) W\)

What is the minimum velocity with which a body of mass m must enter a vertical loop of radius R so that it can complete the loop?

(1) $\sqrt{2\mathrm{gR}}$

(2) $\sqrt{3gR}$

(3) $\sqrt{5gR}$

(4) $\sqrt{gR}$
 

What is the minimum velocity with which a body of mass \(m\) must enter a vertical loop of radius \(R\) so that it can complete the loop?
1. \(\sqrt{2 g R}\)
2. \(\sqrt{3 g R}\)
3. \(\sqrt{5 g R}\)
4. \(\sqrt{ g R}\)$\mathrm{}$