# Shared Flashcard Set

## Details

Chapter 11 Test
N/A
29
Science
04/08/2010

Term
 What is work?
Definition
 The force exerted on an object that causes it to move.
Term
 How is work calculated?
Definition
 work=force x distance
Term
 What is the metric unit for work?
Definition
 Joules (J) = 1N/1s
Term
 When does work occur?
Definition
 Work occurs on an object when the object moves in the same direction in what the force is exerted.
Term
 What are the 6 types of simple machines?
Definition
 1. inclined plane 2. wedge 3. screw 4.lever 5.wheel and axle 6.pulley
Term
 What is an example of each of the six simple machines?
Definition
 inclined plane:stairs wedge:zipper screw:jar lid lever:baseball bat wheel and axle:car pulley:crane
Term
 What is power?
Definition
 The rate at which work is completed
Term
 How is power calculated?
Definition
 power= work / time
Term
 What is the metric unit for power?
Definition
 Watt (W) = 1J/s
Term
 What is a machine?
Definition
 an instrument that allows work to be done in an easier way
Term
 Explain first, second, and third class levers.
Definition
 1st: fulcrum in middle 2nd: resistance in middle 3rd: effort in middle
Term
 Give an example of first, second, and third class levers.
Definition
 1st: see saw 2nd: wheel barrow 3rd:baseball bat
Term
 What is a compound machine?
Definition
 a machine made of two or more simple machines
Term
 What are three effects that machines can have on work?
Definition
 1. change the force 2. change the distance 3. change the direction
Term
Definition
 The number of times a machine increases a force exerted on it
Term
 Can mechanical advantage ever be 100%?
Definition
 No, because of friction
Term
 How do you calculate efficiency?
Definition
 efficiency= output work / input work x 100
Term
Definition
 a machine with an efficiency of 100%
Term
Definition
 a machine with an efficiency that is less than 100%
Term
 What does it mean if mechanical advantage is equal to 1?
Definition
 the output force is equal to the input force
Term
 What does it mean if mechanical advantage is less than 1?
Definition
 the output force is less than the input force
Term
 What does it mean if mechanical advantage is greater than 1?
Definition
 The output force is greater than the input force
Term
 What is a fulcrum?
Definition
 the fixed point around which a lever pivots
Term
 How is a screw like an inclined plane?
Definition
 a screw is an inclined plane wrapped around a post
Term
 How is a wedge like an inclined plane?
Definition
 a wedge is an inclined plane that moves
Term
 What is input force?
Definition
 the force you exert on a machine
Term
 What is output force?
Definition
 the force the machine exerts on an object
Term
 [image]
Definition
 3rd class lever
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