A baseball bat is a third-class lever, with the fulcrum at the end, the force located in the center and the load the point where the ball strikes. Third-class levers require more work to accomplish the job but give the mechanical advantage moving with increased speed.Continue Reading
Brooms and fishing poles are also third-class levers. With the broom, the device sweeps dirt faster than if it were being moved without the lever action. With the fishing pole, the goal is moving the lure or bait far enough from the shore or boat, to the location of the fish.
Many of the actions in daily life require use of third-class levers. The human forearm works in this manner. With the forearm, the elbow serves as the fulcrum, the muscles apply force at their point of attachment at the wrist and the load is generally in the hand. This lever makes the increase in distance very evident. A tiny contraction of the muscle quickly moves the arm several inches, but making the contraction requires a significant amount of energy.
Other types of levers include the first-class lever, where the load is at the opposite end of the lever from the force, with the fulcrum in the middle. First class levers require moving the lever a greater distance but increase force. The second-class lever, where the load is between the fulcrum and the force, also decreases the amount of force required to lift the load.Learn more about Physics