I am lost and need some momentum. Please help me!

Question

A girl on a playground swing starts from rest at an angle θ=33 from the vertical. The chains have length L=4 meters. Find her speed as she passes through the bottom of the swing. Assume no pushing, pumping, air resistance, etc.

In your answer:

Give an answer to 0.01

Answer 1

The initial energy is potential energy and the final energy is all potential

So mgh = 1/2 mv² and v = sqrt(2gh)

But we need to know the height, h, in terms of θ and L. From giometry of the situation, we know that h = L - Lcosθ.

v = sqrt(2gL(1-cosθ))

Please consider a tutor. Take care.