Effort force acts on double the distance the load is raised = MA of 2 Effort force if half the weight of the load = MA of 2
Overview only - next slide has more detailed explanation.
First class levers: pop can, screw driver on lid, seesaw, catapult, pump handle Second Class: wheelbarrow, bottle cap, nut cracker Third Class: fishing pole, snow shovel, ice tongs/tweezers, chopsticks