physics question

Question

A sledder has reached the bottom of a hill and is coasting to the right while slowing down along the loosely-packed snow. Ignore air resistance.

The frictional force is -45 N.

The sledder slows down by -1.5 m/s/s

What is the sledder's mass?

Answer 1

In the direction of travel, the only force acting on the sledder is friction and F = ma or m = F/a.

So m = -45/-1.5 = 30 kg