Energy and Simple Machines

How can simple machines make work easier?

• by decreasing the force needed to complete the task
• by increasing the friction between the machine and the object
• by adding more work on the object than originally applied
• by removing the force of gravity on the object

How does the energy of a roller-coaster cart change as the cart travels from the top of the roller coaster to the bottom?

• The cart has greater kinetic energy at the top than it does at the bottom.
• The cart has no energy at the top and more energy at the bottom.
• The cart has less potential energy at the top than it does at the bottom.
• The cart has potential energy at the top that is transformed to kinetic energy as it moves to the bottom. 

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Movers needed to move a heavy box from the bottom of some stairs to the top of the stairs. They placed a ramp over the stairs and pushed the box up the ramp. Which best explains why the movers used a ramp to move the box?

• The ramp reduced the amount of force needed to move the box.
• The ramp increased the height that the box needed to be moved.
• The ramp reduced the distance that the box needed to be moved.
• The ramp increased the amount of friction needed to move the box.

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Which energy conversion happens when a person shivers and the energy is transferred to make the muscles and joints move?

• kinetic energy to potential energy
• heat energy to kinetic energy
• potential energy to chemical energy
• chemical energy to mechanical energy

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A house uses a roof to carry away large amounts of rain efficiently. A roof composed of two attached inclined planes forms what type of simple machine?

• wedge
• screw
• ramp
• lever

Which machine could be considered to be a type of inclined plane?

• wheel and axle 
• lever
• screw
• pulley 

What does the mechanical energy of a system include?

• the sum of the potential and kinetic energy
• the difference of the potential and kinetic energy
• only the kinetic energy
• only the potential energy

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What form of energy is stored in a battery?

• chemical 
• sound 
• light
• heat

  Energy is transferred in an electrical circuit through

• static protons
• moving protons
• static electrons
• moving electrons

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A wind power project has been proposed for the coastline in St. Lucie County. Windmills would be used to produce energy by converting wind energy into electricity. Electricity would be produced from which energy of the wind?

• potential 
• chemical
• kinetic
• solar 

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