A roller coaster is initially at a height of 40 m above the ground and has an initial velocity of 15 m/s. Using conservation of energy, find the velocity of the roller coaster at a height of 5 m above the ground.
h₁=40 m, h₂=5m, v₁=15 m/s
PE1+KE1 =PE2+KE2
mgh₁+mv₁²/2= mgh₂+ mv₂²/2
Solve for v₂