January 4 2011 DRILL Sketch the pictures below

January 4, 2011 DRILL Sketch the pictures below and answer the questions: • Which lever would be easier to push down, A or B? • Which load will travel the greater distance, A or B? A B U 3 d-L 5

Principle: a law of nature underlying the working of an artificial device • Simple machines work on 2 basic principles: LEVER INCLINED PLANE U 3 d-L 5

• Which class is the lever below? • Describe it. THIRD SECOND CLASS FIRST CLASS U 3 d-L 5

• With a new partner, go over your solutions to the homework. – Are the sketches accurate? – Is the class identification correct? Examples? U 3 d-L 5

WHEEL-and-AXLE • A shaft attached to a disk U 3 d-L 5

WHEEL-and-AXLE • Which class of lever? 2 nd Class U 3 d-L 5

WHEEL-and-AXLE • Which class of lever? 3 rd Class U 3 d-L 5

PULLEYS • Pulleys are grooved wheels attached to an axle. • Generally, what class lever do they act as? 1 st Class U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS • Simple Machines can be: – Force Multiplier: Increases the force applied to the work at hand – Distance Multiplier: Increases the distance the load moves U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS • From the drill: – Which is the force multiplier? • In other words, which arrangement gives you greater strength A B U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS • From the drill: – Which is the distance multiplier? • In other words, which arrangement gives you greater distance A B U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 1. Use the following information to determine the force required to lift the load using a 1 st class lever. L = 100 lbs. DL = 5 ft. DF = 20 ft. F = ? ? 20 ft. F=? 100 lbs. U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 5 ft. 1. Write your equation 2. Substitute values 3. Solve for unknown 20 ft. F=? L x DL = F x DF 100 lbs x 5 ft = F x 20 ft 500 ft-lbs = F x 20 ft F = 25 lbs. U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 2. Use the following information to determine the force required to lift the load using a 1 st class lever. L = 200 lbs. DL = 10 ft. DF = 20 ft. F = ? ? 20 ft. F=? 200 lbs. U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 3. Use the following information to determine the force required to lift the load using a 1 st class lever. L = 100 lbs. DL = 20 ft. DF = 20 ft. F = ? ? 20 ft. F=? 100 lbs. U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 4. Use the following information to determine the force required to lift the load using a 2 nd class lever. 10 ft. L = 100 lbs. DL = 5 ft. DF = 10 ft. F = ? ? F=? 100 lbs. U 3 d-L 5

FORCE/DISTANCE MULTIPLIERS 5. Use the following information to determine the force required to lift the load using a 2 nd class lever. L = 200 lbs. DL = 15 ft. 25 ft. 15 ft. DF = 25 ft. F = ? ? F=? 200 lbs. U 3 d-L 5