Question

A man hauls his 60 kg frame (body, not coordinate system) onto a small fast train. It begins accelerating from rest at 1m/s². He notices the floor of the aisle he is standing in is slippery,
and after 8 seconds he has actually slid backwards (in the train car) at smooth acceleration by 16 meters (it was a long train car).

What was the force of sliding friction applied to his shoes by the floor, and in what direction?

Answer 1