1. The problem statement, all variables and given/known data A roller coaster descends 55m from the top of the first high point to the first low point in the track. The roller coaster converts gravitational potential energy to kinetic energy with an efficiency of 50.0%. What is the velocity of the roller coaster at the bottom of the first low point? 2. Relevant equations Efficiency= (Eout/Ein)100% 3. The attempt at a solution I have no clue how to do it!! I dont understand how to use the efficiency equation to get velocity, please help!