Gravity is
a force that everybody is familiar with and is one of the simplest to
understand. We all know that if you were to throw a ball in the air it
would fall right back down. This force called gravity exerts a constant
acceleration of 9.81 m/sec2 towards the center of the earth. Gravity is
what pulls you down the hill. While gravity is being exerted downward,
a normal force is being exerted on the skier opposing gravity. This normal
force acts perpendicular to the earth's surface, and in this case the
mountain on which the skier is skiing. Lets say for instance the skier
was on a flat surface, both gravity and the normal force would be acting
on the skier but in opposite directions, thereby canceling each other
out and resulting in no movement. However when a skier is on the mountain,
the combination of gravity and the perpendicular normal force result in
the skier being pulled down the mountain at the same angle as the mountain’s
slope. You would definitely not be able to ski powder or jump cliffs without
the force of gravity.
