General Physics I Question: Moment of Inertia Problem Difficulty

In summary, the conversation is discussing a problem statement and relevant equations for a question involving moments of inertia and pulleys. The suggestion is given to assign unknowns for tensions in the strings and draw free body diagrams for each moving mass. It is also mentioned that using an external image server is not acceptable and an attempt at a solution should be provided.
  • #1
i_love_space_and_eng
25
0
Homework Statement
https://imgur.com/a/0CPYhEw
Relevant Equations
Attached.
Hi everyone,
I am honestly pretty confused as to where to start with this. Can anyone give any pointers as to where I could possibly go, for (a) and (b)?
Thanks!
 

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  • #2
i_love_space_and_eng said:
Problem Statement:
Relevant Equations: Attached.

Hi everyone,
I am honestly pretty confused as to where to start with this. Can anyone give any pointers as to where I could possibly go, for (a) and (b)?
Thanks!

You don't need anything on moments of inertia for part a.

For any pulley question, a good place to start is to assign unknowns for the tensions in the strings. If the strings and pulleys are massless and frictionless (other than between string and pulley) you only need one unknown per string. In this question there is only one string.
If a pulley has mass or axial friction then the tensions can be different either side of the pulley, so assign different unknowns.

Next step is to draw a free body diagram for each mass that can move. If a pulley has mass or axial friction, include a FBD for that.
Write force / acceleration and torque / angular acceleration equations for each mass.

Consider which accelerations are the same or related in a known way by the geometry.
 
  • #3
I'm closing this thread because the OP has not put in enough effort.

Posting the question as an image is not acceptable, especially in this case where it can easily be typed. Also, external image servers should not be used (especially imgur, which is not permanent and recycles urls), but all images should be uploaded to PF.

We also require an attempt at a solution.
 
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1. What is the definition of moment of inertia?

The moment of inertia, denoted by I, is a physical quantity that measures the resistance of an object to changes in its rotational motion. It depends on the mass and distribution of the mass within the object.

2. How is moment of inertia different from mass?

Moment of inertia and mass are two different physical quantities. Mass measures the amount of matter in an object, while moment of inertia measures how this mass is distributed around an axis of rotation.

3. How do you calculate the moment of inertia for a simple object?

The moment of inertia for a simple object, such as a point mass or a uniform rod, can be calculated using specific formulas depending on the shape and axis of rotation. For example, the moment of inertia for a point mass rotating around an axis through its center of mass is equal to the mass multiplied by the square of the distance from the axis of rotation.

4. What is the significance of moment of inertia in rotational motion?

Moment of inertia plays a crucial role in rotational motion. It determines how much torque is needed to produce a certain angular acceleration in an object and affects the object's angular speed and kinetic energy. It is also used in various engineering applications, such as designing rotating machinery and analyzing the stability of structures.

5. How does the distribution of mass affect the moment of inertia of an object?

The distribution of mass has a significant impact on the moment of inertia of an object. Objects with a larger concentration of mass towards the axis of rotation have a smaller moment of inertia, while objects with a more spread-out mass have a larger moment of inertia. This is why it is easier to spin a pencil around its long axis than around its tip, as the mass is distributed differently in each case.

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