Question

The parking brake on a 1000 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 2000 kg Volkswagen head-on into the Cadillac and save the children. You may want to review (Page 269) . Part A With what speed should you impact the Cadillac to bring it to a halt?

Answer 1

0.5 mph in the opposite direction

Step-by-step explanation:

`m_1` = Mass of Cadillac = 1000 kg

`v_1` = Velocity of Cadillac = 1 mph

`m_2` = Mass of Volkswagen = 2000 kg

`v_2` = Velocity of Volkswagen

In order to know the speed the system must have the momentum exchange

As the linear momentum of the system is conserved

`m_1v_1+m_2v_2=0\\\Rightarrow v_2=-(m_1v_1)/(m_2)\\\Rightarrow v_2=(1000* 1)/(2000)\\\Rightarrow v_2=-0.5\ mph`

The speed of the impact is given by 0.5 mph in the opposite direction