Question

A 10,000N car is on a roller coaster. at the top of the tallest hill (position 1) the reaches a hieght 36m above the lowest point on the roller coaster (position 2). after accelerating down the hill the roller coaster makes another (position 3) climb that rises 20m about the lowest point calculate the gravitational potentional energy at positions 1 and 3. also calculate the velocity at postition 2.