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What is the Difference between Power and Energy?
The equation that connects power and energy is
Power = Energy ÷ Time.
This equation is important!
is the rate at which energy
Power is measured in Watts. 1 Watt = 1 Joule per second.
What is the Power Output of a Motor?
Q. A motor lifts a
15 kg mass by 3
metres in 8 seconds.
What is the motor's power output ?
A. The motor has transferred rotational energy
into gravitational potential energy.
GPE = mass x gravity x height.
x 10 x 3
= 450 J.
When the 15 kg mass
metres high it has
gained 450 J of gravitational potential energy.
It has gained this energy in 8 seconds.
Power = Energy ÷ Time
= 56·25 W.
The motor's power output is 56·25 Watts.
There is also an equation for power in electricity.
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