Question

You throw a softball (of mass 300 g) straightup into the air. It reaches a maximum altitudeof 16.2 m and then returns to you. Assume no energy is lost by the softball whileit is in the air.What is the kinetic energy of the softball as soon as it leaves your hand?

Answer 1

Answer:

47.628J

Explanation:

If no energy is lost, the energy in when it leaves your hand is equal to the energy at its maximum altitude, so

$\begin{gathered} E_i=E_f \\ KE=\text{mgh} \end{gathered}$

Because the energy at its maximum altitude is potential. So, replacing m = 300 g = 0.3 kg, g = 9.8 m/s², and h = 16.2 m, we get:

$\begin{gathered} KE=(0.3kg)(9.8m/s^2)(16.2m) \\ KE=47.628\text{ J} \end{gathered}$

Therefore, the answer is 47.628J