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A 193 kg curtain needs to e raised 7.5 m, at constant speed, in as close to 5.0 s as possible. The power ratings for three motors are listed as 1.0 kW, 3.5 kW, and 5.5 kW. Which motor is best for the job?

Respuesta :

Answer:

best motor for above purpose is 3.5 kW

Explanation:

As we know that power is defined as the rate of work done

Here we have to raise the curtain so work is done against gravity

So we have

W = mgH

here we know

m = 193 kg

[tex]g = 9.8 m/s^2[/tex]

Now we have

[tex]W = (193)(9.8)(7.5)[/tex]

[tex]W = 14185.5 J[/tex]

now power used in it

[tex]P = \frac{14185.5}{5}[/tex]

[tex]P = 2.8 kW[/tex]

So best motor for above purpose is 3.5 kW

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