Chapter 11, Problem 41A

To determine

Kinetic energy of car.

Answer to Problem 41A

  $KE=202.5\text{ J}$

Explanation of Solution

Given:

Mass of the system, $m=45\text{kg}$ .

Distance traveled, $d=1.8\text{ km }$

Time taken, $t=10\text{ min }$

Formula Used:

Kinetic energy, $\text{KE}=\frac{1}{2}m{v}^2$

Here, m is the mass and visthe velocity

Velocity, $v=\frac{d}{t}$

Here, d is distance and t is time.

Calculation:

Now, substitute the value of d and t and solve.

  $\begin{array}{c}v=\frac{1.8\text{ km}}{10\text{ min}}\\ =\frac{1.8\times 1000\text{ m}}{10\times 60\text{ s}}\\ =\frac{1800}{600}\text{ m/s}\\ \text{=3 m/s}\end{array}$

Now, substitute the values of m and v and solve.

  $\begin{array}{c}KE=\frac{1}{2}\times 45\times 3^2\\ =22.5\times 9\\ =202.5\text{ J}\end{array}$