Question

Hi all, studying for finals!! Help please???
A 35.0-kg child on a swing 2.20 m long is released from rest when the swing supports make an angle of 30 degrees with the vertical. If the speed of the child at the lowest position is 1.97 m/s, what is the energy lost due to friction and air resistance (in Joules)?

Answer 1

Find the initial height from trig then calculate the potential energy from m g h, where
h is the height difference from start to bottom of the motion.

Compare that potential energy with (1/2) m v^2, the kinetic energy at the bottom.
The difference is energy loss.

Answer 2

oooohhhhh I found my mistake:) Thank you very much!!!