The ladder is 5m leaning on a wall, and it is 2.5 m away from the bottom of the wall, so the angle between the ground and the ladder is 60 degrees. The contact interaction between the ladder and the ground has a static friction force of no more than .4 mg, and mg is the weight of the person on the ladder. How high can he climb w/o the ladder slipping? The relevant equations are acceleration = 0 and torque = 0 because the ladder isn't moving. I know that the static friction and normal force from the wall on the ladder must equal 0, and that the normal force from the ground plus the force of gravity must equal 0. Since the torque is 0, I think the total force x length of ladder x cos 60 must equal 0, but I'm not sure how to break up the individual forces and fit them into this equation.