Gravity is an important consideration in the physics
of a hang glider. This is also a concept that we are all very familiar
with. We know that there is a force exerted by the Earth on every object
on the Earth's surface. This force is equal
to the mass of the object multiplied by the acceleration due to gravity, which
is 9.81 m/sec2.
This is important when considering a hang glider because this is the force
that pulls the glider toward the Earth, and would cause a glider with an insufficient
amount of lift to crash. It is important to realize that this force
does exist and that it is always working against a hang glider's flight.