Momentum & Car Crashes

Momentum is tendancy of a moving object to continue to move. The faster an object is travelling or more massive it is, then the harder it is to stop it - its momentum is higher.

Mathematically the momentum of an object is calculated using the equation:

momentum = mass × velocity

The units of momentum are which can be derived from multiplying the units in the equation.

Safety measures in cars and theme park rides are designed to reduce the rate of change of momentum. The higher the rate of change of momentum, the larger the force required and therefore the more chance of injury.

To protect fragile objects, such as humans in car crashes, we need to the time taken to slow them down, to the force applied to them. Safety belts/harnesses, crumple zones and airbags are designed to reduce injury in this way.