So as an exercise I'm trying solve the speed (m/s) of a wagon on a roller coaster. The wagon is moving at 12m/s at a specific moment and I'm trying to find out the speed of the wagon at 27 meters below the initial position.
The correct answer is 26 m/s but I'm trying to understand how to arrive at that answer.
I'm using the mechanical energy principle function but I can't figure out how to determine the mass of the wagon, all I have managed to cobble together is: $V_{1}^2$=$V_{0}^2+2gh_{1}-2gh_{2}$ but this just doesn't work.
All help is appreciated.