A 550 kg car with 120 kg of passengers and cargo is moving at 86 m/s. Suddenly, the driver applies the brakes and the car skids to a stop. What happens to the momentum that the car (and its contents) had before braking?
According to the law of conservation of momentum, the total momentum of an isolated system remains constant unless acted upon by external forces.
Before braking, the car and its contents had a certain momentum which is given by the product of their mass and velocity. The momentum is given by:
Momentum = Mass * Velocity
Therefore, the initial momentum of the car and its contents can be calculated as:
Initial Momentum = (550 kg + 120 kg) * 86 m/s
Initial Momentum = 76,020 kg·m/s
When the driver applies the brakes and the car skids to a stop, an external force is acting upon the car, causing it to change its momentum. As the car comes to a stop, its final momentum would be zero.
Therefore, the momentum that the car and its contents had before braking is reduced to zero after braking.