An Olympic skier moving at 20.0 m/s down a 30.0o slope encounters a region of wet snow, of coefficient of friction μk = 0.740. How far down the slope does she go before stopping?

a.119 m

b.145 m

c.170 m

d.199 m

Option B

Explanation:

Forces acting on the skier-

F1 down the slope  

F2

F3 = friction force    

Net force, down the slope  

Acceleration m/s2  

Acceleration remains constant, initial speed is 20 m/s

Speed at time t is m/s

Distance down the slope at time t is

When the skier stops, her speed is 0. Thus,  

, seconds

Distance travelled in 14.5 seconds (negative because it is down the slope).

Option B is correct

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