Question

Problem 5.15 Piles of snow on slippery roofs can become dangerous projectiles as they melt Consider a chunk of snow at the ridge of a roof with a slope of 27 degree. What is the minimum value of the coefficient of static friction that will keep the snow from sliding down? Express your answer using two significant figures Part B As the snow begins to melt the coefficient of static friction decreases and the snow finally slips. Assuming that the distance from the chunk to the edge of the roof is 65m and the coefficient of kinetic friction is 0.16, calculate the speed of the snow chunk when it slides off the roof. Express your answer to two significant figures and include the appropriate units. Part C If the edge of the roof is 9.0m above ground, estimate the speed of the snow when it hits the ground. Express your answer to two significant figures and include the appropriate units.

Can someone please explain what the question is asking and what each part entails? The answers are above!

Any advice will be greatly appreciated!

Answer 1

m*g*sintheta = us*m*g*costheta

us = tantheta = tan27 = 0.51

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m*g*d*sin27 - uk*m*g*d*cos27 = 0.5*m*v1^2

v1 = sqrt(2*g*d*(sin27 - uk*cos27))

v1 = 6.29 = 6.3 m/s

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energy conservation

0.5*m*v1^2 + m*g*h = 0.5*m*v2^2

v2 = sqrt(v1^2 +2*g*h)

v2 = sqrt((6.3*6.3)+(2*9.8*9)) 14.7 m/s = 15 m/s