Work Energy Theorem

Q.

Why do you feel warm when you rub your palms and touch your cheeks with them? [2 MARKS]

Q.

A force of magnitude 25 N acting on a body of mass 2 kg increases its kinetic energy from 100 J to 200 J. The displacement of the body during this interval is ___ metres.

Q. A spinning wheel $A$ is brought in contact with another wheel $B$ initially at rest. Because of the friction at contact, the second wheel also starts spinning. Which of the following energies of the wheel $B$ increases?

1. Kinetic
2. Total
3. Internal
4. Mechanical

Q. A player kicks a ball of mass 250 g at the centre of a field. The ball leaves his foot with a speed of 10 m/s. Find the work done by the player on the ball.

1. $10.5J$
2. $12.5J$
3. $1.5J$
4. $2.5J$

Q. A perfectly hard billiard ball of kinetic energy $E_k$ collides with another similar ball at rest. After the collision the kinetic energy of the first ball becomes ${E_k}^{\prime }$. Then-

1. ${E_K}^{\prime }>E_K$
2. ${E_K}^{\prime }=E_K$
3. ${E_K}^{\prime }<E_K$
4. ${E_K}^{\prime }=E_K^2$