I have a quetion that I worked out and would love to know if I worked it out alright. Here it goes... A roller coaster of mass 80kg is moving with a speed of 20.0 m/s at position A with a height of 200m. There is no friction and g=10m/s^2. So basically theres a diagram of a rollercoaster with different points and different heights. What is the total energy of the rollercoaster at point A? So, this is at the top of the rollercoaster, so I basically calculated the potential energy. (mass)*(g)*(height). Next, what is the total energy of the roller coaster at point B, which has no height. I calculated the kinetic energy 1/2(mass)(v)^2 and got 1600J Did I do this correct?