Power: Difference between revisions

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When a force is applied over a distance in a unit of time, power is calculated by
When a force is applied over a distance in a unit of time, power is calculated by


:<math>power = \frac{F \Delta r}{\Delta t}</math> where '''F''' is force, '''Δr''' is displacement and '''Δt''' is the duration of time.
:<math>power = \frac{F \Delta r}{\Delta t}</math> = \frac{W}{\Delta t}</math> where '''F''' is force, '''Δr''' is displacement, '''Δt''' is the duration of time and '''W''' is work.


It then follows that instantaneous power is
It then follows that instantaneous power is
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===Simple===
===Simple===


A certain motor is capable of doing 3000 J of work in 11 s.
A certain motor is capable of doing 3000 J of work in 12 s.
What is the power output of this motor?
What is the power output of this motor?
:<math>power = \frac{W}{\Delta t}</math> = \frac{3000 J}{11 s} = 250 watts


===Middling===
===Middling===

Revision as of 17:19, 1 December 2015

Claimed by Aeze3

This topic covers Power.

The Main Idea

Power is the rate of doing work or the amount of energy consumed over an interval of time.

A Mathematical Model

When a force is applied over a distance in a unit of time, power is calculated by

[math]\displaystyle{ power = \frac{F \Delta r}{\Delta t} }[/math] = \frac{W}{\Delta t}</math> where F is force, Δr is displacement, Δt is the duration of time and W is work.

It then follows that instantaneous power is

[math]\displaystyle{ power = F\cdot v }[/math] where v is velocity.

A Computational Model

How do we visualize or predict using this topic. Consider embedding some vpython code here Teach hands-on with GlowScript

Examples

Be sure to show all steps in your solution and include diagrams whenever possible

Simple

A certain motor is capable of doing 3000 J of work in 12 s. What is the power output of this motor?

[math]\displaystyle{ power = \frac{W}{\Delta t} }[/math] = \frac{3000 J}{11 s} = 250 watts

Middling

Difficult

Connectedness

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  2. How is it connected to your major?
  3. Is there an interesting industrial application?

History

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See also

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Further reading

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External links

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References

Chabay, Ruth W.; Sherwood, Bruce A. Matter and Interactions, 4th Edition: 1-2. Wiley.