Question

The parking brake on a 2000 kg Cadillac has failed, and it is rolling slowly, at 1 mph, toward a group of small children. Seeing the situation, you realize you have just enough time to drive your 1000 kg Volkswagen head-on into the Cadillac and save the children. With what speed should you impact the Cadillac to bring it to a halt?

Answer 1

Answer:

Explanation:

Given

mass of Cadillac $m_c=2000\ kg$

Speed of Cadillac $v_c=1\ mph$

mass of Volkswagen $m_v=1000\ kg$

Suppose v is the speed of Volkswagen with which it collide head on with Cadillac.

In order to Stop the Cadillac, Volkswagen must nullify the momentum of Cadillac

Thus momentum of Cadillac and Volkswagen must be same

$m_c\times v_c=m_v\times v$

$2000\times 1=1000\times v$

$v=2\ mph$