Scientists test the safety features of a car by crashing it into a large block of concrete.

A crash test dummy sits in the driver's seat. A video camera records the crash. In one test, the car is travelling at 13 m/s and the dummy has a mass of 83 kg.

a State the equation that links momentum, mass and velocity.


b Calculate the momentum of the dummy.

c In another test, the momentum of the dummy changes by 1250kg m/s in a time of 0.17 s. Calculate the average force acting on the dummy during this time.


d These tests help to make our roads safer. Use ideas about momentum to explain how seat belts and the crumple zones of a car help to reduce injuries during a crash.