A 5630 kg open railroad car coasts along with a constant speed of 8.64 m/s on a level track. Snow begins to fall vertically and fills the car at a rate of 3.50 kg per minute. Ignoring friction with the tracks, what is the speed of the car after 94.8 min?

Answer 1

Lateral momentum remains the same if friction can be ignored.
331.8 kg of snow is added in 94.8 minutes.

5630*8.64 = (5630 + 331.8)*Vfinal

Solve for Vfinal.

I can't imagine frictionless motion on a railroad track that is piled high with snow. In the real world, you can't blindly make wrong assumptions just to make the problem solving easier.

Answer 2

A man with a mass of 64.1 kg stands up in a 61-kg canoe of length 4.00 m floating on water. He walks from a point 0.75 m from the back of the canoe to a point 0.75 m from the front of the canoe. Assume negligible friction between the canoe and the water. How far does the canoe move?