Pulley + spring balance problem.

In summary, the conversation discusses the reading on a spring balance with a light spring passing over a smooth pulley and carrying a mass of 1 kg and two weights of masses 1 kg and 2 kg. The question is whether the reading is affected by the tension above the spring balance or only the reading below it. The suggested approach is to consider the weight of the spring balance and add 1 N to the reading. The possibility of acceleration is also mentioned. Ultimately, it is agreed that the only way to be sure is to conduct an experiment.
  • #1
Lexadis
11
1

Homework Statement


A light spring passing over a smooth pulley carries a spring balance of mass 1 kg and two weights of masses 1 kg and 2 kg. the reading on the balance will be

Homework Equations


3. The Attempt at a Solution [/B]
to my knowledge whatever the tension above the spring balance the reading will not change, it is only affected by the reading below it. Therefore I considered
reading = weight of spring balance + 1N
Reading = 20N
But I'm not sure whether this is the right approach. Should the mass of spring be considered? Or will there be some sort of acceleration taking place?

Thank you.
 

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  • #2
Hi,

You want to draw a free body diagram of the spring balance.

Is your 1 N a typo? DId you mean 10 N ?

To help you form an idea of the situation:
Suppose the spring balance + 1kg weight hangs from a nail in the wall.
What does the balance reading show ?
What is the force on the nail ?​
 
  • #3
image.jpg

It was 10 N ^^
So.. It would look like this: (attachment)
Therefore, reading = 10N
Would that be okay?
Thank you
 
  • #4
I think I agree.
Just for fun: what would the reading be if the spring balance were turned upside down ?
 
  • #5
20N?
I'm not very sure though..
 
  • #6
I agree - again :smile: !
I suppose the only way to be really sure is to do the experiment...
 
  • #7
True :D
Thank you very much :)
 

Related to Pulley + spring balance problem.

1. What is a pulley + spring balance problem?

A pulley + spring balance problem is a physics problem that involves calculating the forces and motion of objects connected by a pulley system, with the added complication of a spring attached to one of the objects. The goal is to determine the unknown quantities, such as the tension in the pulley system or the displacement of the spring, using principles of mechanics and energy.

2. How do I approach solving a pulley + spring balance problem?

The first step is to draw a diagram of the system and label all known quantities and unknowns. Then, use Newton's laws of motion and Hooke's law to set up equations for each object in the system. Finally, solve the equations simultaneously to find the unknown quantities.

3. What are some common mistakes to avoid when solving a pulley + spring balance problem?

One common mistake is forgetting to include the weight of the pulley itself in the calculations. Another mistake is not considering the direction of the forces and ensuring they are consistent throughout the problem. It is also important to carefully track units and make sure they are consistent.

4. Can a pulley + spring balance problem have multiple solutions?

Yes, a pulley + spring balance problem can have multiple solutions. This can happen when there are multiple unknown quantities or when the system is in equilibrium, meaning there are multiple combinations of values that satisfy the equations. It is important to carefully check the solutions to ensure they make physical sense.

5. What real-life applications can a pulley + spring balance problem have?

Pulley + spring balance problems can be found in many real-life situations, such as elevator systems, weightlifting machines, and even in the human body (such as the pulley system of tendons and muscles in the hand). They are also commonly used in engineering and physics experiments to study the principles of mechanics and energy.

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