Question

A 3 kg ball is thrown downward at 4 m/s from a height of 1.5 m. What is the kinetic energy of the ball as it leaves the thrower’s hand?

Answer 1

The kinetic energy of a ball thrown at 4 m/s is

$$E=\frac12 mv^2=\frac12 ·3·4^2=24\text{ J}.$$