Physics Mechanics Assignment Question

Question

Sarah (m=81.2 kg) is traveling at a speed of 18.1 m/s at the top of a 11.5 m high roller coaster loop. Determine Sarah's speed at the bottom of the loop. Include a diagram 

Answer 1

mv₁²/2 + mgh = mv₂²/2; v₂ = √v₁² + 2gh = (18.1² + 2·9.8·11.5)^1/2 = 23.5 m/s