soda water opener - The arm of force longer than the arm of resistance, stapler - lever always save effort, doesn't save effort - The effort force is larger than the resistance force , Newton - the effort force and resistance force are measured in, The law of lever - The law of lever Force x its arm= Resistance x its arm, effort force arm - The distance between the effort force and fulcrum, first class lever - force arm= Resistance arm, centimeter - The effort arm is measured in , scissors - from the first class lever, coal holder - lever used to avoid dangers,

second lesson lever

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