Question

You must not drive at excessive speeds. If you double the speed of a car, the force of impact in a crash is

- Doubled.
- Four times as great.
- Five times as great.

Answer 1

Four times as great.

Step-by-step explanation:

The force of impact is given by the impulse

Impulse is the change in momentum of an object

u = Initial velocity of the car

v = Final velocity of the car = 0

m = Mass of the car

`J=p_f-p_i\\\Rightarrow J=mv-mu\\\Rightarrow J=m(v-u)\\\Rightarrow J=mu`

When velocity is four times greater

`J=4mu`

So, if velocity is increased 4 times the momentum will increase four times thus increasing the force of impact by four times.