A 15 meter, 478 Newton uniform ladder rests against a frictionless wall, making an angle of 60.0 degree with the horizontal.
(a) Compute the horizontal and vertical forces exerted on the base of the ladder by the Earth when a 770 Newton fire fighter is 4.00 meter from the bottom.
horizontal N
vertical N
(b) If the ladder is just on the verge of slipping when the firefighter is 9.00 meter up, find the coefficient of static friction between ladder and ground?