Pulley Question : find tension in rope (Help )

In summary, the conversation discusses solving a physics problem involving a 6kg block and tension force. The initial attempt at solving the problem did not take into account the acceleration, leading to an incorrect answer of 29.4. After realizing the mistake, the correct answer of 41 was obtained by setting the net force for each object equal to the Fnet. The conversation also suggests making a clear free body diagram and writing equations accordingly when solving such problems.
  • #1
Lori

Homework Statement


upload_2017-11-12_16-21-11.png


Homework Equations



F = ma

The Attempt at a Solution


So , i drew a freebody diagram for the 6k gram block, and the tension to the right of I call T2.
Therefore, the force of gravity component parallel to T2 is (6*9.8)sin30. Therefore, T2 is equal to this value which i found is 29.4! However, i don't think this is right!
 

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  • #2
Lori said:
However, i don't think this is right!
You think correctly: you forget about the acceleration...
 
  • #3
BvU said:
You think correctly: you forget about the acceleration...
what do you mean? :(

I see... i got the answer 41. I had to set netforce for each of them to ma
 
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  • #4
He is saying that you neglected to include the acceleration.
 
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  • #5
Dr.D said:
He is saying that you neglected to include the acceleration.
i realized that i should be take the sum of the forces on each object and setting it equal to the Fnet. I only realize this till now! Few more hours until the exam :(!
 
  • #6
Lori said:
i realized that i should be take the sum of the forces on each object and setting it equal to the Fnet. I only realize this till now! Few more hours until the exam :(!
In these questions first try to make free body diagram clearly and then write equation accordingly.
 

1. How does a pulley affect the tension in a rope?

When a rope is attached to a pulley, the tension in the rope is evenly distributed throughout the length of the rope. This means that the tension in the rope is the same on both sides of the pulley, regardless of the weight or force being applied to the rope.

2. How do I calculate the tension in a rope when using a pulley?

To calculate the tension in a rope when using a pulley, you will need to know the weight or force being applied to the rope, the number of pulleys in the system, and the direction of the force. You can then use the formula T = (W/n) + F, where T is the tension, W is the weight or force, n is the number of pulleys, and F is the additional force required to overcome the friction of the pulley.

3. How does the number of pulleys affect the tension in a rope?

The number of pulleys in a system has a direct impact on the tension in the rope. As the number of pulleys increases, the tension in the rope decreases. This is because the weight or force is distributed among more pulleys, reducing the amount of tension required in the rope to support the weight.

4. Can the tension in a rope ever be greater than the weight or force applied?

No, the tension in a rope can never be greater than the weight or force applied to it. However, in certain situations, such as a rope being pulled over a pulley, the tension in the rope may be slightly higher due to the additional force required to overcome the friction of the pulley.

5. How can I increase the tension in a rope when using a pulley?

To increase the tension in a rope when using a pulley, you can either increase the weight or force being applied to the rope, or you can decrease the number of pulleys in the system. This will require a greater amount of tension in the rope to support the weight, as there are fewer pulleys to distribute the weight.

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