An open railroad car of mass 2445 kg is coasting with an initial speed of 22 m/s on a frictionless, horizontal track. It is raining, and water begins to accumulate in the car. After some time, it is found that the speed of the car is only 5 m/s. How much water (in kilograms) has accumulated in the car?

1 answer

conservation of momentum applies

2445*22=(2445+M)5
solve for Mass rainwater M in kilograms.