# Answer to Question #15534 in Mechanics | Relativity for Dirghayu Raichura

Question #15534

a piece of ice slides down a 45degree incline in twice the time it takes to slide down a frictionless 45degree incline. find the coefficient of kinetic friction between ice and incline.

the answer is 0.75 but i want the solution the answer is given in the back side of my book . i.e. yugbodh physics class 11th.

the answer is 0.75 but i want the solution the answer is given in the back side of my book . i.e. yugbodh physics class 11th.

Expert's answer

If the time is doubled by the presence of friction, the acceleration

is

reduced by a factor 4. (That is because S = a * t^2 / 2 remains the

same).

The friction is therefore 3/4 of the component of the weight

down the

incline.

m * g * cos 45 * k = (3/4) * m * g * sin 45, where k is the

kinetic

friction coefficient.

k = 3/4 = 0.75

is

reduced by a factor 4. (That is because S = a * t^2 / 2 remains the

same).

The friction is therefore 3/4 of the component of the weight

down the

incline.

m * g * cos 45 * k = (3/4) * m * g * sin 45, where k is the

kinetic

friction coefficient.

k = 3/4 = 0.75

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