How much work is done on a bucket when pulling it up?

  • Thread starter Thread starter BlueQuark
  • Start date Start date
  • Tags Tags
    Work Work done
Click For Summary
SUMMARY

The discussion centers on calculating the work done on a bucket with a mass of 6.75 kg when it is pulled up a distance of 4.00 m using a rope over a frictionless pulley. The correct calculation of work, based on the tension force equal to the weight of the bucket (66.21 N), yields 264.84 J. However, the answer key from "Sears and Zemansky's University Physics With Modern Physics, 12th edition" incorrectly states the work done as 3.60 J. The participants agree that the initial calculation is accurate and suspect an error in the textbook.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Familiarity with the concept of work in physics
  • Knowledge of tension forces in equilibrium systems
  • Basic grasp of gravitational force calculations
NEXT STEPS
  • Review the concept of work-energy principles in physics
  • Study tension forces in pulley systems
  • Examine common errors in physics textbooks and how to identify them
  • Learn about gravitational force calculations and their applications
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding work calculations in pulley systems.

BlueQuark
Messages
13
Reaction score
1

Homework Statement


An old oaken bucket of mass 6.75 kg hangs in a well at the end of a rope. The rope passes over a frictionless pulley at the top of the well, and you pull horizontally on the end of the rope to raise the bucket slowly a distance of 4.00m.
A). How much work do you do on the bucket in pulling it up?

Homework Equations


##W = FS##
##W = ΔKE##
##ΣFy = T - mg##

The Attempt at a Solution


First, I assumed the problem was implying that the bucket was in equilibrium when it said it was moving slowly. So since the weight is ##(9.81)(6.75) = 66.21 N##, the tension force must be equal to that.

So, ##W = FS##. ##W = (66.21)(4) = 264.84 J##. This seemed like the correct answer to me, but when I look at the back of the book, it says the answer is 3.60 J.

Where did I go wrong here? Thanks!
 
Physics news on Phys.org
I'd say your answer is correct. What book/problem is this from?
 
Doc Al said:
I'd say your answer is correct. What book/problem is this from?
That's what I thought too. It's from "Sears and zemansky's University Physics With Modern Physics, 12th edition".

I guess there was a mistake or something in the answer key.
 
BlueQuark said:
I guess there was a mistake or something in the answer key.
Yep.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
7K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K