Question

a car weighs 3600 kg is traveling at 21.0 m/s. the driver doesn?t notice a red light and rear-ends another car at rest. both cars stick together and move with a speed of 9.0 m/s. what is the mass of the car that was at rest?

Answer 1

Below

Step-by-step explanation:

Use law of conservation of momentum

momentum before crash = momentum of the system after crash

3600 kg * 21 m/s = (3600+ x ) * 9

solve for x = 4800 kg