A $400-N$ child is in a swing that is attached to a pair of ropes $8\mathrm{.}00$ m long. Find the gravitational potential energy of the child$-$Earth system relative to the child's lowest position when $($a$)$ the ropes are horizontal, $($b$)$ the ropes make a $30-$degree angle with the vertical, and $($c$)$ the child is at the bottom of the circular arc. d$)$ e$)$ & f$)$: Repeat this measuring gravitational potential energy from the highest point.

D$,$e and f please!