Conceptual torque problem with multiple sized pulleys

In summary, the conversation discusses a conceptual question about torque and acceleration. The student's reasoning is incorrect because they think that the clockwise torque is greater than the counterclockwise torque because the disk is accelerating clockwise. However, a free body diagram would show that m1 is accelerating up and m2 is accelerating down, meaning that the tension in T1 should be greater than T2. The student is missing the definition of torque and how it is related to acceleration.
  • #1
crybllrd
120
0

Homework Statement


This is a six part conceptual question that is not difficult. However, the last part I am struggling with.
What is wrong with the following student's reasoning:
"The clockwise torque is greater than the counterclockwise torque because the disk is accelerating clockwise. For this to happen, T2 must pull harder on the disk than T1."

Here's a pic I drew:

2h6eq74.jpg


The Attempt at a Solution



Well I know the first sentence is correct.
But I also thought the second one is too.
A free body diagram would show m1 accelerating up, and m2 down. Therefore tension in
T1>T2.
What am I missing here?

EDIT: m1=m2
 
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  • #2
It is correct that T1 must be greater than T2 if m2 accelerates downward. The reasoning is wrong. To accelerate the disk clockwise, the torque of T2 has to be greater than the torque of T1. How is torque defined?

ehild
 

Related to Conceptual torque problem with multiple sized pulleys

1. What is a conceptual torque problem with multiple sized pulleys?

A conceptual torque problem with multiple sized pulleys is a physics problem that involves calculating the torque (rotational force) exerted on a system of pulleys with different sizes and masses. This type of problem is commonly used to illustrate concepts such as mechanical advantage and the conservation of energy.

2. How do you approach solving a conceptual torque problem with multiple sized pulleys?

The first step in solving a conceptual torque problem with multiple sized pulleys is to draw a diagram of the system and label all the pulleys, masses, and distances involved. Then, use the equation T = Fr (torque = force x distance) to calculate the torque exerted by each pulley on the system. Finally, apply the principle of conservation of energy to determine the final state of the system.

3. What are some common mistakes made when solving a conceptual torque problem with multiple sized pulleys?

One common mistake is not correctly identifying the direction of the forces and torques involved. Another mistake is not taking into account the different radii of the pulleys when calculating torque. It is also important to remember to use the correct units for force and distance in the torque equation.

4. How does the number of pulleys in a system affect the torque calculation?

The number of pulleys in a system does not affect the calculation of torque. However, the number of pulleys can affect the mechanical advantage of the system, which is the ratio of output force to input force. More pulleys can increase the mechanical advantage and make it easier to lift heavy masses.

5. What real-world applications use the principles of a conceptual torque problem with multiple sized pulleys?

Conceptual torque problems with multiple sized pulleys are commonly used in engineering and construction, such as in cranes and elevators. They are also used in everyday objects like bicycle gears and pulley systems in weightlifting machines. Understanding the principles of torque and mechanical advantage is crucial in designing efficient and effective machines.

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