A man pulls a sled at a constant velocity across a horizontal snow surface. if a force of 80 n is being applied to the sled rope at an angle of 53° to the ground, what is the force of friction between sled and snow?

A constant velocity implies the two forces must be equal and opposite.

Friction acts horizontal to the ground, therefore we must find the force applied to the sled rope that acts horizontal to the ground.

Do this by resolving:

Force = 80cos53

The force opposing this is equal, and so also = 80cos53 = 48 N (2 sig. fig.)