Question

Calculate the impulse necessary to stop a 1500 kg car travelling at 90 km per hr.

Answer 1

Step 1: Given that:

The mass(m) of the car= $1500kg$

Initial velocity of the car($u$) = $90km{h}^{-1}=90\times \frac{5}{18}m{s}^{-1}=25m{s}^{-1}$

Final velocity of the car($v$) = $0$

Step 2: Calculation of impulse:

We have,

Impulse= Change in momentum of the body

= $mv-mu$

Thus,

Impulse on the car will be;

$=1500kg\times 0-1500kg\times 25m{s}^{-1}$

$=-37500kgm{s}^{-1}$

$=-3.75\times {10}^{4}kgm{s}^{-1}$

Thus,

Impulse on the car will be $3.75\times {10}^{4}kgm{s}^{-1}$