Question

A ball is falling after rolling off a tall roof The ball has what type of energy.

Answer 1

Answer:

Linear and rotational Kinetic Energy + Gravitational potential energy

Explanation:

The ball rolls off a tall roof and starts falling.

Let us first consider the potential energy or more specifically gravitational potential energy ($mgh$; $m$ = mass of the ball, $g$ = acceleration due to gravity, $h$ = height of the roof). This energy comes because someone or something had to do work to take the ball to the top of the roof against the force of gravity. The potential energy is naturally maximum at the top and minimum when the ball finally reaches the ground.

Now, the ball starts to roll and falls off the roof. It shall continue rotating because of inertia (Newton's first law). This contributes to the rotational kinetic energy ($\frac{1}{2}I\omega^2$; $I$=moment of inertia of the ball & $\omega$ = angular velocity).

Finally comes the linear kinetic energy or simply, kinetic energy ($\frac{1}{2}mv^2$) which is caused due to the velocity $v$ of the ball.