Q1-Week 2 (SCIENCE 8)- Work, Power, and Energy

• ​Work is useful in defining energy.

• ​Without energy and power, you cannot create work.

​Work is done whenever a force produces movement.

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​Work is done to transform energy from one form to another.

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For work to be done the force exerted should be parallel to the displacement.

This is not an example of work. The wall is not displaced. A force must cause a displacement in order for work to be done.

​No part of the force is parallel to the displacement.

​This is an example of work. There is a force (gravity), that acts on the book which causes it to be displaced in a downward direction

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As she lifts the baby the force exerted on the baby is parallel to the displacement.

Formula:​

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​UNIT FOR WORK (W) is JOULES (J) =

REVIEW YOUR GEOMETRY​

Power is the rate of doing work.

​Where:

​W = work

​F= force parallel to the displacement

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​FORMULA:

​S.I. Unit of is (J/s or watts (W)

​1 joule/second (J/s) = 1 watt (W)

​1000 watts = 1 kilowatt (kW)

​1 horsepower (hp) =746 watt

​Is the RATE of doing work

​is the energy possessed by bodies in motion

​Stored energy.

​The higher an object, the higher the gravitational potential energy.

​Depends on the mass and speed of the body.

Since speed ( is doubled it takes,

​its KE is increased by a factor of 4

​An object in an elevated position is said to have gravitational potential energy

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