0 kg child on a 3.00 m long swing is released from rest when the ropes of the swing make an angle of 29.0 with the vertical.

A 31.0 kg child on a 3.00 m long swing is released from rest when the ropes of the swing make an angle of 29.0° with the vertical.(a) Neglecting friction, find the child's speed at the lowest position.1ans.: 2.99 m/s (b) If the speed of the child at the lowest position is 2.60 m/s, what is the mechanical energy lost due to friction?2ans.: 31.5 J