Object at rope: work to lift it

In summary, the conversation discusses the work done by a person in raising an old oaken bucket from a well using a rope and pulley system. The force exerted by the person can be calculated using the equation F = W/s, where W is the work done and s is the displacement. The work done is also equal to the change in potential energy, which can be calculated using the equation mg(H2-H1), where m is the mass of the bucket and g is the acceleration due to gravity. The total work done is equal to the sum of the work done by the person and the change in potential energy. The answer in the book is 3.6 J, which may be different from the calculated value due to rounding
  • #1
iwonde
31
0
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 4.00 m.

So far, I have:
F = force exerted by me
s = displacement
W_F=F x s

How do I find F? Does it have anything to do with the tension of the rope?
 
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  • #2
Work done is also the change in potential energy.
 
  • #3
I'm sorry, I meant to ask for the work done by me.
So,
H= height
H_1 = 0
H_2 = 4m
Work_total = change of potential energy = mg(H_2 - H_1) = 264.6
and W_total = W_me + mgH_1 = 264.6J
W_me = 264.6 J
Did I do something wrong, because it doesn't seem right.
 
  • #4
Looks Ok to me. What are you having trouble with?
 
  • #5
The answer in the book is 3.6 J.
 
  • #6
What was the question in full? Are you sure that's the answer to this question?
 

Related to Object at rope: work to lift it

1. How does the weight of an object affect the work required to lift it?

The weight of an object directly affects the amount of work required to lift it. The heavier the object, the more work is needed to overcome its gravitational force and lift it off the ground.

2. Can the length of the rope change the amount of work needed to lift an object?

Yes, the length of the rope can affect the amount of work needed to lift an object. The longer the rope, the more work is required to pull it and lift the object. This is because the longer the rope, the more distance the object has to cover to reach its lifted position.

3. Does the speed at which an object is lifted affect the work required?

The speed at which an object is lifted does not affect the work required. The work done to lift an object is determined by the weight of the object and the distance it is lifted, not the speed at which it is lifted.

4. How does the angle of the rope affect the work needed to lift an object?

The angle of the rope can affect the work needed to lift an object. If the rope is at a steeper angle, more work is required to lift the object. This is because the steeper the angle, the more the force is directed towards pulling the object vertically rather than horizontally, increasing the amount of work required.

5. Is the work required to lift an object the same as the potential energy gained by the object?

Yes, the work required to lift an object is equal to the potential energy gained by the object. This is due to the conservation of energy principle, which states that energy cannot be created or destroyed, only transferred from one form to another. In this case, the work done to lift the object is transferred into potential energy as the object gains height.

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