Question

PLZ HELP I DON'T UNDERSTAND!! a boy is playing catch with his friend. He throws the ball straight up. When it leaves his hand, the ball (2kg) is traveling 10m/s. Whats the ball's kinetic energy just as it leaves the boy's hand? What is the potential energy of the ball when it reaches the highest point?

Answer 1

Explanation:

The mass of a ball, m = 2 kg

It is traveling with a speed of 10 m/s

The ball's kinetic energy just as it leaves the boy's hand is calculated as follows :

$K=\dfrac{1}{2}mv^2\\\\K=\dfrac{1}{2}\times 2\times (10)^2\\\\=100\ J$

The ball's kinetic energy just as it leaves the boy's hand is 100 J. The potential energy of the ball when it reaches the highest point is same as the kinetic energy as it leaves the boy's hand.

Hence, the required kinetic and potential energy is 100 J.