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~christina~

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## Homework Statement

A 120 V motor has a mechanical power output of 2.50hp It is 90% effiecient in converting power that it takes in by electrical transmission into mechanical power.

a) find current in motor

b) find energy delivered to the motor by electrical transmission in 3.00 h of operation

c) If the electrical company charges $0.160kWh what does it cost to run the motor for 3.00h?

## Homework Equations

## The Attempt at a Solution

**a) find current in motor**

[tex]P=I \Delta V[/tex]

and I got

I= 17.08A

**b) find energy delivered to the motor by electrical transmission in 3.00 h of operation**

would I use this..

[tex]P \Delta t= I \Delta V ( \Delta t ) [/tex] ?

Thanks