A father pulls his son, whos mass is 25 kg and who is sitting on a swing with ropes of length 3 meters, backward until the ropes make an angle of 33.6 degrees with respect to the vertical. He then releases his son from rest. What is the speed of the son at the bottom of the swinging motion?

Answer 1

How high?
Draw it.
h = L - L cos 33.6 = L(1-cos33.6)
= 3(1-.833) = .501 meters up

Potential energy increase = m g h
= 25 (9.81) (.501)

Ke = (1/2)(25) v^2 = 25(9.81)(.501)
cancel the mass and
solve for v = sqrt(2 g h) as usual :)

Answer 2

the answer is wrong
it will equal = 3.135