A 16.0 m uniform ladder weighing480 N rests against a friction less wall. The ladder makes a 61.0° angle with the horizontal.
1. Discover the horizontal and vertical forces the ground exerts on the base of the ladder when an 840 N fire fighter is 4.20 m from the bottom.
2. If the ladder is now on the verge of slipping when the fire fighter is 8.90 m up, what is the coefficient of static friction among ladder and ground?