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Machines p108. A lever is a simple machine. The work done on one side equals the work done on the other. A lever is a FORCE MULTIPLIER !. Five ropes around the pulleys. One rope is pulled. Rope is pulled 50cm. Mass is lifted 10 cm. 100 N of force on this side.
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Machines p108 A lever is a simple machine. The work done on one side equals the work done on the other. A lever is a FORCE MULTIPLIER!
Five ropes around the pulleys. One rope is pulled. Rope is pulled 50cm Mass is lifted 10 cm 100 N of force on this side. 500 N of force on this side. (F x d)left = (F x d)right (100 N) (50 cm) = (500 N) (10 cm) Pulleys change the direction of force. Pulley systems multiply force.
Efficiency Useful energy output Efficiency = Total energy input What if our buddy pulled with a force of 110 N for 1.0 m and the weight of 500N was lifted 0.20 m. (Fx d)in = (F x d)out output input (F x d)out (500)(0.2) Efficiency = = = 0.91 (F x d)in (110)(1.0)
Comparison of Kinetic Energy and Momentum p110 Metal bullet delivers its momentum as it penetrates the wood. A little wobble as momentum is transferred to block Rubber bullet delivers its momentum. Then, it does it again as it bounces. Twice as much wobble because of bounce. If the speed of the metal bullet is doubled, then it would cause the same wobble as the rubber bullet above. But, doubling the speed would increase the KE by four times. With four times the damage. Momentum and Kinetic Energy are not the same thing.
This time dart bounces Note needle in nose so that it doesn’t bounce Wood is not damaged by impact. KE drives needle into wood causing damage. The End