Chapter 4.1, Problem 3PP

To determine

To calculate: the average force exerted by the brakes on the car.

Answer to Problem 3PP

  $\underset{\_}{6000\text{ N}}$ force is exerted by the brakes on the car.

Explanation of Solution

Given data:

Work done by the brakes on the car, $W=240,000\text{ J}$

Distance travelled by the car while the brakes are applied, $d=40\text{ m}$

Formula used:

Work Equation:

  $W=Fd$

Where $W$ is work in joules, $F$ is the applied force in newton and $d$ is the distance moved by the object in meters

Calculation:

As per the problem,

  $\begin{array}{l}W=240,000\text{ J}\\ d=40\text{ m}\end{array}$

Substitute the values of work and distance in the rearranged work equation to get force:

  $\begin{array}{l}W=Fd\\ F=\frac{W}{d}\\ F=\frac{240,000\text{ J}}{\text{40 m}}\\ F=6000\text{ N}\end{array}$

Conclusion:

  $\underset{\_}{6000\text{ N}}$ force is exerted by the brakes on the car.