Notesale: Turn your study into money

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WORK AND ENERGY
Work
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energy transfer to an object by an applied force over a measured distance
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However, when holding a heavy box on your shoulder,
you may feel pain and break into sweat but you are not doing work on the box because you are
not moving it
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"No work is done if the force you apply does not make the object move
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"

How is work measured?

✓ In order to say that work is done on an object, there must be a force applied to it
and the object moves in the direction of the applied force
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It is often expressed in Newton-meter
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after the English scientist James Prescott Joule
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m
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Work = change in energy
W = ∆E

Kinetic Energy
Kinetic energy is possessed by moving bodies
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Being initially at rest, the car's kinetic energy is zero
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(see Figure 15) the car acquires a speed and kinetic energy equal
to:

KE = ½ mv2
The work is equal to the change in kinetic energy of the car
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Bodies at rest possess potential energy
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F = ma,

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Where the object is a is the acceleration due to gravity
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In equation,

W = ∆PEgrav

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If the gravitational potential energy of the object at its initial position is zero,

then the final gravitational potential energy can be written as

PEgrav = magh

POWER
*** The rate of doing work is known as power
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*** And when we speak of speed, we always think of time
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Example:
°°° Two students of the same weight are helping a charity drive
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The students climb 32 meters up, one in 7 minutes and
the other in 10 minutes
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Thus,
some other factors are influencing the two students
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Power is the rate of doing work or transforming energy
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•••> This SI unit
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For historical reasons, the horsepower is occasionally used to describe
the power delivered by a machine
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