Student Librarian Does Work on Book

AI Thread Summary
The discussion focuses on calculating the work done by a student librarian when moving a 22N book. The key formula for work is clarified as W = Fdcos(θ), emphasizing that only the force component in the direction of displacement contributes to work. The librarian lifts the book to a height of 1.25m and carries it 8.0m before placing it on a shelf at 1.35m. Participants discuss the need to consider the angles involved in the movements to accurately compute the work done. Understanding the correct application of the work formula is essential for solving the problem.
Iceclover
Messages
59
Reaction score
0

Homework Statement


a student librarian picks up a 22N book from the floor to a height of 1.25m. He carries the book 8.0m to the stacks and places the book on a shelf that is 1.35m high. How much work does he do on the book


Homework Equations



W=Fd

The Attempt at a Solution



Am i just supposed to add up all the distances and then use my W=Fd formula?
 
Physics news on Phys.org
Iceclover said:

Homework Statement


a student librarian picks up a 22N book from the floor to a height of 1.25m. He carries the book 8.0m to the stacks and places the book on a shelf that is 1.35m high. How much work does he do on the book


Homework Equations



W=Fd

The Attempt at a Solution



Am i just supposed to add up all the distances and then use my W=Fd formula?
Your formula for work is not quite correct. Only the component of the force in the direction of the displacement does work.For example, to find our how much work is done in carrying the book 8.0 meters to the stacks, answer the following question: How much force acts in the direction of the 8 meter displacement?
 
what is the correct formula for work then?
 
Iceclover said:
what is the correct formula for work then?
W = Fdcos\theta
where \theta is the included angle between the force vector and the displacement vector.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Work Done by Librarian on 2.2kg Book
Replies
1
Views
1K
Help finding the work done given 3 different distances?
Replies
1
Views
1K
Questions about Energy (Work and Power)
Replies
2
Views
1K
How to find the amount of work done on an object
Replies
6
Views
17K
Compare Work & Power of Student A Lifting 50-N Box
Replies
9
Views
3K
How to calculate the angle using work, displacement and 2 forces?
Replies
9
Views
3K
When Does a Book Slide Off a Tilting Shelf?
Replies
32
Views
6K
How Much Work Does Ryan Do Lifting and Carrying Potatoes?
Replies
7
Views
2K
Energy/Work Problem: Friction of sliding down pole
Replies
5
Views
4K
Solving Work and Force of Wagon and Child
Replies
11
Views
3K

Hot Threads

Recent Insights

Back
Top