Question

A motorist attempts to push her car back to the road after losing control in a snow storm and skidding to the middle of a frozen pond. The mass of the car is 1890kg and the mass of the motorist is 50kg. When the motorist pushes on the car, it moves forward with a speed of 10cm/s. At what speed does the motorist fly backwards?

Answer 1

Given

mass of the car is M = 1890 kg

speed of car is V = 10 cm/s = 0.1 m/s

mass of motorist is m = 50 kg

Let v be the speed of motorist.

By conservation of linear momentum,

Initial momentum before pushing = Final momentum after pushing

Before pushing, they are at rest. Therefore momentum is 0

therefore,

negative sign is because the velocities are in opposite directions.

therefore, the speed of motorist is