Question

A ski starts from rest and slides down a 21 ∘ incline 75 m long.

A. If the coefficient of friction is 0.085, what is the ski's speed at the base of the incline?

Express your answer using two significant figures.

B. If the coefficient of friction is 0.085, what is the ski's speed at the base of the incline?

Express your answer using two significant figures.

Answer 1

here,

theta = 21 degree

length of incline , s = 75 m

a)

uk = 0.085

the accelration , a = net force /effective mass

a = ( m * g * sin(theta) - uk * m * g * cos(theta))/(m)

a = (9.81 * sin(21) - 0.085 * 9.81 * cos(21)) m/s^2

a = 2.74 m/s^2

the speed of ski at the bottom of incline , v = sqrt(2*a * s)

v = sqrt(2 * 2.74 * 75)

v = 20.3 m/s

b)

uk = 0.085

the accelration , a = net force /effective mass

a = ( m * g * sin(theta) - uk * m * g * cos(theta))/(m)

a = (9.81 * sin(21) - 0.085 * 9.81 * cos(21)) m/s^2

a = 2.74 m/s^2

the speed of ski at the bottom of incline , v = sqrt(2*a * s)

v = sqrt(2 * 2.74 * 75)

v = 20.3 m/s