Question

As Jane approaches a stop sign, she applies a braking force of 10,000 N. Her car has a mass of 2,000kg and is moving with a velocity of +20 m/s. What is the impulse imparted to bring the car to astop?B.Using the impulse you found above, how long will it take for Jane's car to stop?

Answer 1

Given that the force applied by Jane is F =10000 N. The mass of car is m = 2000 kg and the initial velocity is u = +20 m/s and the final velocity is v = 0 m/s as the brakes are applied.

We have to find the impulse and the time taken.

Impulse can be calculated by the formula,

$I\text{mpulse = m(v-u)}$

Substituting the values, the magnitude of impulse will be

$\begin{gathered} \operatorname{Im}\text{pulse = 2000}\times20 \\ =40000\text{ kg m/s} \end{gathered}$

The time can be calculated by the formula

$\operatorname{Im}\text{pulse = Force}\times time$

Substituting the values, time will be

$\begin{gathered} \text{time =}\frac{\text{Impulse}}{force} \\ =\frac{40000}{10000} \\ =4\text{ s} \end{gathered}$