Question
4. At Sugarloaf Ski Resort in Maine, the Snowbrook trail is a beginner hill that slopes down at a gradual 9.0° incline. If a beginner snowboarder begins from a vertical height of 115 m, how fast will the novice be going when she reaches the bottom? Hint: you can assume the trail is icy and thus frictionless 5. During a tennis match, one of the players smashes the ball into the ground, and it bounces off the ground with a speed of 15 m/s. If a fan in the stands catches the ball when it has a speed of 11 m/s, how high is the fan above the court? You can ignore air resistance.
Explanation / Answer
4.
By Conservation of energy
KI+Ui=Kf+Uf
(1/2)mVi2+mghi=(1/2)mVf2+mghf
since it starts from rest Vi=0 and at the bottom of the incline hf=0
0+mghi=(1/2)mVf2+0
=>Vf=sqrt(2gh)=sqrt(2*9.8*115)
Vf=47.5 m/s