Chapter 4.2, Problem 16PP

To determine

To calculate: the kinetic energy of the baseball.

Answer to Problem 16PP

The kinetic energy of the baseball is $\underset{\_}{\text{120 J}}$ .

Explanation of Solution

Given data:

Mass of the baseball, $m=0.15\text{ kg}$

Speed of the baseball, $v=40.0\text{ m/s}$

Formula used:

Kinetic Energy Equation:

  $KE=\frac{1}{2}m{v}^2$

Where $KE$ is the kinetic energy of the object in joules, $m$ is the mass of the object in $\text{kg}$ and $v$ is the speed of the object in $\text{m/s}$ .

Calculation:

As per the problem,

  $\begin{array}{l}m=0.15\text{ kg}\\ v=40.0\text{ m/s}\end{array}$

Substitute the values of mass and speed in the kinetic energy equation:

  $\begin{array}{l}KE=\frac{1}{2}m{v}^2\\ KE=\frac{1}{2}(0.15\text{ kg)(40}{\text{.0 m/s)}}^2\\ KE=\frac{1}{2}(0.15{\text{ kg)(1600 m}}^2{\text{/s}}^2\text{)}\\ KE=120\text{ J}\end{array}$

Conclusion:

The kinetic energy of the baseball is $\underset{\_}{\text{120 J}}$ .