Answer to Question #76150 in Physics for aluwani

Question

Suppose a motorcyclist rides a certain high-speed motorcycle. He reaches top speed and then coasts up a hill. The maximum height reached by the motorcyclist was 250 m. If 2.55 ×105 J of kinetic energy was dissipated by friction, what was the initial speed of the motorcycle? The combined mass of the motorcycle and motorcyclist is 250 kg.

Answer 1

PE = mgh = 250 ∙ 9.81 ∙ 250 = 613125 J
PE +W_Friction = KE
KE = 6.13∙〖10〗^5 J+ 2.55∙〖10〗^5 = 8.68 ∙〖10〗^5 J
1/2 mv^2 = KE
v =√(8.68 ∙〖10〗^5 2/250)
v = 83.3 m/s