A uniform plank the length of 6.1 m, weight of 445 N rests on the ground and a frictionless roller at the top of a wall 3.05 m high. The plank is in equilibrium at any value of θ greater than or equal to 70 degrees but slips if θ is < 70 degrees. Discover the coefficient of friction among the plank and the ground. Utilize the point of origin for forces about the point where the ground and the plank meet.