What Is the Minimum Power Needed for an Elevator Motor?

[jman565]

Homework Statement

A 1.0X10^3kg elevator carries a maximum load of 800.0 kg. A constant frictional force of 4.0x10^3N retards the elevator's motion upward. What minimum power in kilowatts must the motor deliver to lift the fully loaded elevator at a constant speed of 3.00m/s?

Homework Equations

This is part of my problem that I don't understand.

The Attempt at a Solution

I haven't made an attempt because I do not know the equation. I'm studying for my college finals and this is a question that my friend made for a review. Unfortunately, he is visiting a family member who is expecting to pass soon. Any advice would be great!

 

[Dick]

Work is force times distance. At constant speed and force, power is force times velocity. That's what you need. What's with the inane poll? The purpose of life is to answer Forum questions from people who don't make an effort.

 

[jman565]

i arrived 65.7832 kw.
Is that correct? man he should have made an answer key.

 

[jman565]

Work is force times distance. At constant speed and force, power is force times velocity. That's what you need. What's with the inane poll? The purpose of life is to answer Forum questions from people who don't make an effort.

is 65.7832 kw the right answer?

 

[Dick]

is 65.7832 kw the right answer?

My answer is a little bit different. Not much. What are you using for g?

 

[jman565]

9.812 m/s2

 

[Dick]

That's the difference. I was using 9.8.

 

[jman565]

what did u get?

 

[Dick]

64.92kW. The difference is just in the value of g.

 

[jman565]

can u check it with 9.812? i don't have a calculator...

 

[Dick]

Why? No, I don't want to. Get a calculator. I checked your answer.

 

[jman565]

omgravity i don't have one. anywhere. at all. my friend has it. the one in CA right now visiting his family member that could die very soon. i really need your help. it won't take you long at all. please?

 

[Dick]

I've consigned you to the 'joke' column. I also hit "report". You'll need another alias. A-hole.

 

[jman565]

i reported u too.

 

[vanesch]

This silly thread is done.