The kid on the right has a lot of
momentum!
When
playing
on
a
swing
set,
you
are
really working a pendulum.
When
sitting stationary on the swing, like the kid on the left, the only
force acting is gravity, and there is tension coming from the chains
connected to the swing. As momentum builds, the swing......swings
and the forces acting on the swing look like figure 2. Where m =
mass g = gravity, T = tension, and F = the force due to pumping your
legs.
Figure
1
Figure 2