Just got owned on this exam question

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In summary, the conversation discusses a problem involving two masses, a pulley with radius R, and a frictionless peg. The goal is to find the acceleration of m1, the tensions of the rope on each side of the pulley, the angular velocity of the pulley, and the inertia of the pulley. The conversation mentions the given variables of m1, m2, radius R, and the distance traveled by m2 in 5 seconds. The conversation also includes attempts at solving the problem using conservation of energy and free-body diagrams, as well as the realization that the missing variable of the pulley's mass is needed to fully solve the problem.
  • #1
anotherghost
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Homework Statement



You've got two masses, m1 and m2, hanging from opposite ends of a rope that goes over a pulley with radius R. Both the masses are suspended by the rope alone and the pulley is on a frictionless peg. M2 moves down by x2 meters in 5 seconds. I believe that's all the variables we were given - m1, m2, radius R, and 2 meters in 5 seconds. EDIT: The pulley doesn't slip.

Now find the accelleration of m1, the tensions of the rope on each side of the pulley, the angular velocity of the pulley, and the inertia of the pulley.

Homework Equations


The Attempt at a Solution



I have no idea how to do this without being given the mass of the pulley or its inertia.

Started out with m1gx + m2gx = (1/2)m1v^2 + (1/2)m2v^2 + (1/2)I(V/R)^2 + m1g*2x.
 
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  • #2
Since the question asks for acceleration, you probably don't want to use conservation of energy because conservation of energy equations have no acceleration terms. Instead, use plain old free-body diagrams and Newton's second law.

Since the acceleration is constant and d=v0t+(1/2)at^2, you can calculate acceleration with the fact that m2 dropped by 5 m in 2 s. See where this takes you.
 
  • #3
Oh man, duh. I can't believe I didn't see that. I can get the rest of it if I have that a no problem. Guess I'll just have to chalk that one up to a brain fart, hope I'll still get partial credit. :)
 

Related to Just got owned on this exam question

1. What does it mean to "get owned" on an exam question?

Getting owned on an exam question means that you did not answer the question correctly or fully, resulting in a low or failing grade on that particular question.

2. How can I avoid getting owned on exam questions?

To avoid getting owned on exam questions, it is important to study and prepare well in advance. Make sure to understand the material and practice with sample questions. It is also helpful to manage your time effectively during the exam and read each question carefully before answering.

3. Is getting owned on an exam question a bad thing?

While getting owned on an exam question may not feel good, it can be a learning opportunity. It can show you where you need to improve and what areas you may need to focus more on in your studies.

4. How should I handle getting owned on an exam question?

If you get owned on an exam question, don't panic. Take a deep breath and move on to the next question. You can always come back to the question later if you have time. After the exam, reflect on why you may have gotten owned and use that information to improve for future exams.

5. Can getting owned on an exam question affect my overall grade?

It depends on the weight of the question and the overall grading system for the exam. If the question is worth a significant portion of the exam grade, it can have a significant impact on your overall grade. It is important to do your best on every question to ensure a good overall grade.

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