Question

A 25.0-kg child on a 3.00-m-long swing is released from rest when the ropes of the swing make an angle of 31.0° with the vertical.
(a) Neglecting friction, find the child's speed at the lowest position.

m/s

(b) If the actual speed of the child at the lowest position is 2.50 m/s, what is the mechanical energy lost due to friction?

J

Answer 1

a)mgh = 1/2 mv^2
h = 3-3cos31
solve for v
b) mgh - 1/2mv^2 = energy lost