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# Work and Power,definition and machines doing work

this is a project of science
by

## nicole broser

on 29 April 2011

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#### Transcript of Work and Power,definition and machines doing work

work requires motion: for a forece to do work on an object, some of the force must act in the same direction as the object moves. if there is no movement, no work is done. what is work? work is the pruduct of force
and distance.work is done
when a force acts on an. work depends on direction: Any part of a force that does not act
in the direction of motion doesn´t work on an object. All of the force actss in the same direction as a thing moves. calculating work: the work done is calculated by multiplying the constant force acting in the direction of motion byh the distance that the object moves.
WORK=FORCE x DISTANCE Units of work: when using SI in the work formula, the force is in newton, and distance is in meters. the product of force and distance results in units os newtonmeters: joule(SI of work). Using the work
formula: Work and power,
definition
and machines
doing work: if is easy to calculate the work done
by a weigh liftes.
Work Formula:
WORK= force X distance
WORK= 1600 N X 2.0m
WORK= 32000N.m=3200 J

WHAT IS POWER Power is the rate of doing work Doing work at a faster rate requires more power. To increase power, you can increase the amount of work done in a given time, or you can do a given amount of work in less time. calculating power you can calculate power by dividing the amount of work done by the time needed to do the wok. POWER = work time The SI unit of power is the watt = one joulemper second James Watt and Horsepower A horsepower is a unit of power.
It is equal to about 746 watts. The
horsepower was first defined by
James Watt. James Watt was looking for
a way to compare the power outputs of
Horse was a logical choice for comparsion as
they were the most commonly used source of power
in the 1700s. Watt did not want to exaggerate the power of his steamengines.
work and machines a machine is a device that changes a force.
Machines do or make work
easier to do. They change the size
of a force needed, the direction of
a force, or the distance over which
a force acts. increasing
force increasing
distance if a machine increases
the distance over which you
exert force, then it decreases the
amount of force you need to exert. some machines decreases the applied force but increase the distance over which the force is
exerted.
A machine that decreases distance through which you
exert a force increases the amount
of force required. Changing direction some machines changes
the direction of an applied force.
Not only can machines change the amount of force and the distance the force acts through, but they can also change the direction of the force.
Work input and work output work input work output is the force you
exert on a machine. is the force that is exerted by a machine best drowing. work input to a machine work output of a machine the distance the input force acts through is know as the input
distance. The work done by the input force
acting through the input distance is called the work input.
The work input equals the input force multiplied by the input distance.
the distance the output force is exerted through is the output distance. the work output of a machine is the output force multiplied by the output distance. if is easy to calculate the work done
by a weigh liftes.
Work Formula:
WORK= force X distance
WORK= 1600 N X 2.0m
WORK= 32000N.m=3200 J

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