Question

An 80 kilogram skier slides on waxed skis along a horizontal surface of snow at a constant velocity while pushing with his poles. What is the horizontal component of the force pushing him forward?

Answer 1

From Newton's First law, if velocity is constant than the net force on the body is zero; or net force in horizontal direction is zero and net force in vertical direction is also zero.

If we assume that the there is negligible friction between waxed skies and snow, than there will be no frictional force on skies in horizontal direction and as net force in horizontal direction is zero, hence the horizontal component of the force pushing him forward is also zero.