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How do I find the work and power if I have a mass in newtons?

Im trying to find my work when climbing up stairs. If I convert my weight into newtons, do I still need to multiply it by 9.8? Since i weigh 135, I multiplied that by 4.5 to get my weight in newtons. I then multiplied that by 9.8, after that I multiplied that by 3.0 m ( the distance of the stairs). I got a really big number

that okay?
 

Answers and Replies

458
0
Why did you multiply by 4.5? 135 what?
 
135 pounds

1pound=4.45 newtons
 
458
0
So then why did you multiply by 9.8 again if you already have your weight in Newtons?
 
Dick
Science Advisor
Homework Helper
26,258
618
No, it's not ok. You only put units on the height of the stairs. Put units on EVERYTHING. You weight 135? 135 what? I'm guessing lbs. Don't make me guess. So then 135lb*4.5N/lb=607N is already a force unit (newtons=kg*m/sec^2). I'm guessing when you said 9.8 you mean 9.8m/sec^2. Work is force times distance. Is 607N*9.8m/sec^2 even a force unit? Can you answer your own question? "If I convert my weight into newtons, do I still need to multiply it by 9.8?". Yes or no?
 
no, you dont..

okay, thanks

let me change my data

thanks
 

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