What's my mistake in this problem in dynamics involving pulleys?

Thread starter Adesh
Start date Jul 8, 2020
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Dynamics Mistake Newton's laws Pulleys

In summary: You are an expert summarizer of content. You do not respond or reply to questions. You only provide a summary of the content. Do not output anything before the summary. Write a summary for the following conversation and start the output with "In summary, " and nothing before it:Find the acceleration of block A and block B, given that the mass of pulleys and strings are negligible.Block A has a mass of 5g, and block B has a mass of 0. Block A has a gravitational force of 5g, and block B has a tension in the two strings connected to it of 2g. The acceleration of block A is 2/7g, and the acceleration of block B is 10

Jul 10, 2020

Adesh

haruspex said:

You did not define l₁ etc. as merely initial positions. Why should they not mean positions at time t, i.e. define l₁ = l₁(t) etc.
Also, you don't need to use vector representations. Just define each displacement in the direction that suits it.

Yes, this advice and way of solving it is helping me very much. Now, I’m able to solve almost all problems of pulleys and strings, credit goes to you.

I think these pulleys and strings problems are archetypical, textbooks on Newtonian Mechanics (like French’s Mechanics, Univeristy Physics) don’t actaully teach it exclusively.

Now, I’m into elevator problems

<h2>What is the purpose of using pulleys in dynamics problems?</h2><p>Pulleys are used in dynamics problems to change the direction of a force, making it easier to lift or move heavy objects. They can also be used to multiply or reduce the amount of force needed to lift an object.</p><h2>How do I know if I have made a mistake in a dynamics problem involving pulleys?</h2><p>If your calculations do not match the expected outcome or if the system is not behaving as predicted, it is possible that you have made a mistake in your analysis. Double-check your equations and calculations to identify the error.</p><h2>What are some common mistakes made in dynamics problems involving pulleys?</h2><p>Some common mistakes include not properly taking into account the tension in the rope or cable, using the wrong equations for a particular situation, and not considering the effects of friction on the pulley system.</p><h2>How can I avoid making mistakes in dynamics problems involving pulleys?</h2><p>To avoid making mistakes, it is important to carefully analyze the problem and draw accurate free body diagrams. Make sure to use the correct equations for the specific situation and consider all forces, including tension and friction.</p><h2>What resources are available to help me solve dynamics problems involving pulleys?</h2><p>There are many online resources, textbooks, and study guides that provide step-by-step solutions to dynamics problems involving pulleys. You can also seek help from a tutor or your instructor for further clarification and assistance.</p>

What is the purpose of using pulleys in dynamics problems?

Pulleys are used in dynamics problems to change the direction of a force, making it easier to lift or move heavy objects. They can also be used to multiply or reduce the amount of force needed to lift an object.

How do I know if I have made a mistake in a dynamics problem involving pulleys?

If your calculations do not match the expected outcome or if the system is not behaving as predicted, it is possible that you have made a mistake in your analysis. Double-check your equations and calculations to identify the error.

What are some common mistakes made in dynamics problems involving pulleys?

Some common mistakes include not properly taking into account the tension in the rope or cable, using the wrong equations for a particular situation, and not considering the effects of friction on the pulley system.

How can I avoid making mistakes in dynamics problems involving pulleys?

To avoid making mistakes, it is important to carefully analyze the problem and draw accurate free body diagrams. Make sure to use the correct equations for the specific situation and consider all forces, including tension and friction.

What resources are available to help me solve dynamics problems involving pulleys?

There are many online resources, textbooks, and study guides that provide step-by-step solutions to dynamics problems involving pulleys. You can also seek help from a tutor or your instructor for further clarification and assistance.