A $1000-$kg roller coaster car is initially at the top of a rise, at point A$.$ It then moves $135$ ft$,$ at an angle of $40\mathrm{.}08$ below the horizontal, to a lower point B$.($a$)$ Choose the car at point B to be the zero configuration for gravitational potential energy of the roller coaster$$Earth system. Find the poten$-$tial energy of the system when the car is at points A and B$,$ and the change in potential energy as the car moves between these points. $($b$)$ Repeat part $($a$),$ setting the zero configuration with the car at point A$.$