A 16 kg child on a playground swing moves
with a speed of 9.5 m/s when the 2 m long swing is at its lowest point.
The acceleration of gravity is 9.81 m/s^2
What is the angle that the swing makes
with the vertical when the swing is at its
highest point? Answer in units of degrees.
For this problem, i solved for KE first. KE = 1/2mv^2, so plugging in some numbers I get 76 joules. Then I plug this into the PE equation (PE = mgh), so when 76 = (16kg)(9.81)(h) the height I get is .4841997m.
From this point on, I think I get stuck. I understand that energy is conserved, but how do I find out the angle that the swim makes? I tried using pythagorean's theorem, but that doesn't seem to work because the swing is always 2m long (which gives it a round opposite).