How Can I Calculate Energy and Power for an 800W Electric Motor?

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Homework Help Overview

The discussion revolves around calculating energy and power for an 800W electric motor used to raise a load, focusing on the energy supplied, wasted energy, output power, and efficiency of the motor.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between power, energy, and time, with attempts to clarify the correct equations. There are questions about how to calculate the energy supplied to the motor and the implications of the given data.

Discussion Status

Some participants have provided guidance on the correct equations relating power, energy, and time. There is an ongoing exploration of how to apply these equations to the specific problem, with some expressions of understanding emerging.

Contextual Notes

The original poster expresses uncertainty and concern about an upcoming exam, which may influence their approach to the problem. There is a policy in place requiring participants to show attempts at solving the problem before receiving help.

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Energy Calculation ~~help

Homework Statement


Question )
An 800W electric motor is used to raise a load. In 120s, the load gains
24,000 J of gravitational potential energy from the motor
Calculate :
a) electrical energy supplied to the motor
b) energy wasted by the motor
c) output power of the motor
d) efficiency of the motor


Homework Equations


W=J/s


The Attempt at a Solution


I have no idea //

i've got a big school exam next Monday T-T
help me~
thank you
 
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Welcome to Physics Forums.

What is the equation that relates power, energy, and time?

You'll have to show an attempt at solving the problem before getting help (sorry, but that's our policy).
 


Redbelly98 said:
Welcome to Physics Forums.

What is the equation that relates power, energy, and time?

You'll have to show an attempt at solving the problem before getting help (sorry, but that's our policy).

Power = Energy x Time
Energy = Power / Time
Time = Power / Energy

Is this right ??
 


Not quite, it's

Power = Energy / Time
etc.

Using that, can you find (a) the energy supplied to the 800 W motor?
 


Redbelly98 said:
Not quite, it's

Power = Energy / Time
etc.

Using that, can you find (a) the energy supplied to the 800 W motor?

AH~~~~~
now i got it ~:D thank you
 

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