What is the work done on a bucket hanging in a well?

AI Thread Summary
To determine the work done on a bucket hanging in a well, the problem involves calculating the work done by the person pulling the bucket and the work done by gravity. The individual attempted to use the formula W = F d, calculating the force as the weight of the bucket (9.8 N multiplied by 6.75 kg) and the distance as 4.00 m, resulting in 264.6 J. However, there is confusion regarding the correct answer, which is stated as 3.6 J in the textbook, leading to skepticism about the book's accuracy. The discussion highlights the importance of understanding the forces at play when pulling the bucket slowly, emphasizing that the upward force must be slightly greater than the weight of the bucket. Clarification on the calculations and assumptions is needed to resolve the discrepancies in the work done.
enian
Messages
23
Reaction score
0

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?
(b) How much work does gravity do on the bucket?
(c) What si the total work done on the bucket?

The Attempt at a Solution


I couldn't get part (a). I may not be understanding it right.
I said..
W = F d
W = (9.8*6.75) * 4.0m
W = 264.6 J
*assuming by slowly they mean the upward force is just slightly more than the weight

but the answer in the back of the book for a is 3.6J??
 
Physics news on Phys.org
i guess the book is wrong..3.6 J to pull a 6.75kg 4meters... not even in the moon would be that work...
 
Is my method right though?
 
Last edited:

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Similar threads

How much work is done on a bucket when pulling it up?
Replies
3
Views
2K
Why Does Gravity Affect Work Done in a Simple Pulley System?
Replies
3
Views
3K
Calculating Work on a Bucket Hanging in a Well
Replies
3
Views
7K
What is the work done on the bucket in a frictionless pulley problem?
Replies
1
Views
4K
Work & Energy: Lifiting Water from a Well
Replies
22
Views
2K
Solve a Simple Work Problem and Find Out Why You're Wrong
Replies
3
Views
3K
Object at rope: work to lift it
Replies
5
Views
2K
Find work on raising a bucket on a rope
Replies
3
Views
3K
Determine acceleration when lifting a bucket.
Replies
6
Views
2K
What is the work done on cart by the string?
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top