Chapter 9, Problem 40A

Calculate the number of joules of kinetic energy a 1-kg book has when tossed across the room at a speed of 2 m/s.

$\text{Work}=\Delta \text{KE}$

To determine

Kinetic Energy.

Answer to Problem 40A

  $KE=2\text{J}$

Explanation of Solution

Given:

Mass ok book, $m=1\text{kg}$

Speed, $v=2\text{m/s}$

Formula Used:

The kinetic energy is given as,

  $KE=\frac{1}{2}m{v}^2$

Where, $m$ is mass and $v$ is speed of object.

Calculation:

On substituting the given values, kinetic energy is

  $\begin{array}{c}KE=\frac{1}{2}\times 1\times 2^2\\ =2\text{J}\end{array}$

Conclusion:

Therefore, the kinetic energy of the book is $KE=2\text{J}$