A skier starts from rest at the top of a frictionless incline of height 20.0 m,
ID: 2106642 • Letter: A
Question
A skier starts from rest at the top of a frictionless incline of height 20.0 m, as shown in the figure. At the bottom of the incline, the skier encounters a horizontal surface where the coefficient of kinetic friction between skis and snow is 0.188. Neglect air resistance.
Explanation / Answer
a)mgh = 1/2 * mv2
or v2=2gh = 2*10*20 = 400
v=20 m/s
b) frictional force = mg = 0.188 * m * 10
Deacceleration = -0.188*10=-1.88
u=20,v=0,a=-1.88,S=?
S= (v2-u2)/2a = -400/-3.76 = 106.38 m
c)Work done by friction on incline = mgcos * h/cos = 0.188 * m * 10 * 20 = 37.6 m
So Energy at bottom = mgh - 37.6m = 162.4m
For velocity at bottom
1/2 * mv2 =162.4 m
or v2=324.8
v=18 m/s
frictional force on horizontal track = mg = 0.188 * m * 10
Deacceleration = -0.188*10=-1.88
u=18,v=0,a=-1.88,S=?
S= (v2-u2)/2a = -400/-3.76 = 86.17 metre
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