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Book on table moved to Shelf

  • Thread starter talaroue
  • Start date
303
0
1. Homework Statement
A 1.7 kg book is lying on a 0.99-m-high table. You pick it up and place it on a bookshelf 2.43 m above the floor.
How much work does gravity do on the book


2. Homework Equations
Wmg=mgYi-mgYf


3. The Attempt at a Solution

I thought that is the correct equation so I simply just plugged and chugged but it came out wrong. What did I do wrong?
 

berkeman

Mentor
55,769
5,849
1. Homework Statement
A 1.7 kg book is lying on a 0.99-m-high table. You pick it up and place it on a bookshelf 2.43 m above the floor.
How much work does gravity do on the book


2. Homework Equations
Wmg=mgYi-mgYf


3. The Attempt at a Solution

I thought that is the correct equation so I simply just plugged and chugged but it came out wrong. What did I do wrong?

It might just be a sign error. Note that the question asks for the work done by gravity on the book. But the postive work done is by the person lifting the book....
 
303
0
Sorry guys I jumped the gun on this one. I soon realized that I just had to reverse my orginal equation. The equation that I have is for the work done by your hands picking the book up.
 
303
0
I just posted as you posted yeah, thanks for the help!
 

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