A 21.0 kilogram child on a 3.00 meter long swing is released from rest when the ropes of the swing make an angle of 26.0 degree with the vertical.
(1) Ignoring friction, determine the child's speed at the lowest position.
m/s
(2) If the speed of the child at the lowest position is 2.10 m/s, find the mechanical energy lost due to friction?
J