A homeowner is trying to move a stubborn rock from his yard. By using a a metal rod as a lever arm and a fulcrum (or pivot point) the homeowner will have a better chance of moving the rock. The homeowner places the fulcrum a distance ?=0.288 mfrom the rock, which has a mass of 465 kg, and fits one end of the rod under the rock's center of weight. If the homeowner can apply a maximum force of 671 N at the other end of the rod, what is the minimum total length ? of the rod required to move the rock? Assume that the rod is massless and nearly horizontal so that the weight of the rock and homeowner's force are both essentially vertical. The acceleration due to gravity is ?=9.81 m/s2.

A 50 N hand and forearm are held at a 35° angle to the vertically oriented humerus. The CG of the forearm and hand is located at a distance of 12.5 cm from the joint center at the elbow, and the elbow flexor muscles attach at an average distance of 2.5 cm from the joint center. (Assume that the muscles attach at an angle of 35° to the forearm bones.) How much force must the forearm flexors exert if a 50 N weight is held in the hand at a distance along the arm of 25 cm?

A beam rests on a fulcrum, 1.4 meters from one end. A weight of 495 kg is suspended from this end causing the beam to balance. If the weight of 495 is suspended on the opposite end of the beam, it is necessary to suspend a 2795 kg weight on the first end in order to effect an even balance. Use g = 9.81 m/s2.

A homeowner is trying to move a stubborn rock from his yard. By using a a metal rod as a lever arm and a fulcrum (or pivot point) the homeowner will have a better chance of moving the rock. The homeowner places the fulcrum a distance d = 0.255 m from the rock, which has a mass of 405 kg, and fits one end of the rod under the rock's center of weight. If the homeowner can apply a maximum force of 695 N at the other end of the rod, what is the minimum total length L of the rod required to move the rock? Assume that the rod is massless and nearly horizontal so that the weight of the rock and homeowner's force are both essentially vertical. The acceleration due to gravity is g = 9.81 m/s². L =