A window washer attempts to lean a ladder against a frictionless wall.He finds that the ladder slips on the ground when it is placed at an angle of less than 75 ° to the ground but remains in place when the angle is greater than 75 ° .The coefficient of static friction between the ladder and the ground:
A)is 0.13
B)is 0.27
C)is 1.3
D)depends on the mass of the ladder
E)depends on the length of the ladder

Question

A window washer attempts to lean a ladder against a frictionless wall.He finds that the ladder slips on the ground when it is placed at an angle of less than 75 °  to the ground but remains in place when the angle is greater than 75 ° .The coefficient of static friction between the ladder and the ground:
A)is 0.13
B)is 0.27
C)is 1.3
D)depends on the mass of the ladder
E)depends on the length of the ladder

Quizplus · Accepted Answer

The coefficient of static friction is given by the formula:μs = tan θwhere θ is the angle of repose. In this case, the angle of repose is 75°. Therefore, the coefficient of static friction is:μs = tan 75° = 0.13

A Window Washer Attempts to Lean a Ladder Against a Frictionless