Tension pulley of a well problem

In summary, the tension in the rope in part b is 202 N, as determined by applying the equations of equilibrium and using the weight of the bucket as a reference point. The constant velocity of the bucket in part b implies that the tension in the rope remains the same as in part a.
  • #1
metalmagik
131
0
Part a of the drawing shows a bucket of water suspended from the pulley of a well; the tension in the rope is 101.0 N. Part b shows the same bucket of water being pulled up from the well at a constant velocity. What is the tension in the rope in part b?

p4-46.gif


Is the tension the same? that's all i can think about for it, since it's moving at a constant velocity in (b), which means its not accelerating, it should have the same tension, I believe. Any hints please?
 
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  • #2
metalmagik said:
Is the tension the same? that's all i can think about for it, since it's moving at a constant velocity in (b), which means its not accelerating, it should have the same tension, I believe. Any hints please?

Draw a free body diagram for part (a) to determine the weight of the bucket. Then you can determine the tension of the rope in (b) by drawing a free body diagram of the bucket again. (Hint: constant velocity implies that you must use the equation of equilibrium, i.e. the sum of vertical forces acting on the bucket must equal zero.)
 
  • #3
Thanks for the response radou.

So in (b), since there are two tension forces...doesn't this not matter? Isn't there still only one going up and the tension is the same, 101 N?
 
  • #4
metalmagik said:
Thanks for the response radou.

So in (b), since there are two tension forces...doesn't this not matter? Isn't there still only one going up and the tension is the same, 101 N?

In (a), there are two same tension forces. In (b), there is one tension force.
 
  • #5
I see...so in (b), is the tension in the rope holding the bucket 50.5? If so, I still do not understand how to calculate the other tension, since it is not directly acting on the bucket. This just does not make sense to me. I figured out the bucket has a mass of 10.3 kg...and that's about as far as I got calculation wise.
 
  • #6
metalmagik said:
I see...so in (b), is the tension in the rope holding the bucket 50.5? If so, I still do not understand how to calculate the other tension, since it is not directly acting on the bucket. This just does not make sense to me. I figured out the bucket has a mass of 10.3 kg...and that's about as far as I got calculation wise.

Again, first look at (a). The bucket is at rest, so you can apply the equation of equilibrium, i.e. it is intuitive clear that the following must hold: mg=2*101 = 202. Now, since you know the weight of the bucket (the force of gravity acting on it), you can jump to part (b). Since there is constant velocity involved, you can apply the equations of equilibrium, too (the sum of vertical forces applied onto the bucket must equal zero), so, you have mg = T, where T is the tension you need to find.
 
  • #7
I don't know why I can't think straight tonight...I do have a little bit of a cold...sorry for all of this...

since mg = 2 * 101 and mg = T...T must equal 202 N, correct?
 
  • #8
metalmagik said:
I don't know why I can't think straight tonight...I do have a little bit of a cold...sorry for all of this...

since mg = 2 * 101 and mg = T...T must equal 202 N, correct?

Correct. :smile:
 
  • #9
Thank you very much...If you're not busy with anything else and are in the mood for helping, respond to this...doing a webassign while sick is no picnic...if not thank you very much anyway.
 

What is a tension pulley?

A tension pulley is a mechanical device that is used to redirect and increase the tension in a rope or belt. It usually consists of a wheel with a groove around its circumference and a mechanism to hold the rope or belt in place.

What is the purpose of a tension pulley in a well?

In a well, a tension pulley is used to support and guide the wire or cable that is connected to the pump. It helps to reduce the strain on the motor and maintain a consistent tension on the wire, ensuring smooth operation of the pump.

How can I tell if the tension pulley of a well is malfunctioning?

If the tension pulley is malfunctioning, you may notice a decrease in water flow or pressure from the well. You may also hear unusual noises coming from the well or notice that the wire or cable is loose or damaged. It is important to regularly check and maintain the tension pulley to prevent any issues.

What are some common problems with tension pulleys in wells?

Some common problems with tension pulleys in wells include rust or corrosion, misalignment, and wear and tear on the wheel or bearing. These issues can lead to decreased tension on the wire or cable, which can affect the performance of the pump and potentially cause damage to the well system.

How can I troubleshoot tension pulley problems in a well?

If you suspect that the tension pulley in your well is causing issues, it is best to consult a professional. They will be able to inspect the pulley and determine the cause of the problem. In some cases, the tension pulley may need to be replaced or repositioned to ensure proper tension on the wire or cable.

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