Unequal Masses on a Pivot Rod: What Does it Mean?

In summary, the conversation is about a homework question involving a pivot rod with unequal masses. The spheres in question are small enough to be treated as point particles, and the question asks if the equation I=2/5mr^2 can be used to solve it. The expert responds that the equation can be used, but the unequal masses cannot be ignored, as they have no rotational inertia. The person asking the question then realizes they can use the given information and thanks the expert for their help.
  • #1
PSEYE
13
0
I have a homework question that is referring to a pivot rod with unequal masses.


The spheres are small enough that they can be considered point particles.

what exactly does this mean?

I know how to solve the equation, but I'm assuming I can't use the I=2/5mr^2 to solve it.
If the masses are negligable, why are they unequal to begin with? LOL
 
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  • #2
It means that you can ignore the sizes of the spheres, not their masses. (They have no rotational inertia about their center of mass.)
 
  • #3
nvm, I just used what they were asking me to use, I just assumed the program knew that m_1 was lighter than m_2 and I was assuming correctly.
 
  • #4
Thanks Doc Al!
 

1. What is unequal masses on a pivot rod?

Unequal masses on a pivot rod refers to a system in which two objects of different masses are attached to a rod that can rotate freely around a fixed point, or pivot. This creates an unequal distribution of weight on either side of the pivot point.

2. How does unequal masses on a pivot rod affect the system?

The unequal distribution of weight on either side of the pivot point causes a torque, or rotational force, to act on the system. This results in rotational motion and can cause the system to move in a specific direction.

3. What factors can influence unequal masses on a pivot rod?

The main factor that influences unequal masses on a pivot rod is the difference in mass between the two objects. However, the distance between the objects and the pivot point also plays a role, as well as the center of mass of each object.

4. What are some real-world examples of unequal masses on a pivot rod?

One example is a see-saw, where two children of different weights sit on either end of a plank that is balanced on a pivot. Another example is a weighing scale, where the unequal masses of objects are used to determine their weight.

5. How is unequal masses on a pivot rod relevant to scientific studies?

Understanding the effects of unequal masses on a pivot rod is crucial in many scientific fields, such as physics, engineering, and biomechanics. It helps explain the principles of torque and rotational motion, and can be applied in various practical applications, such as designing machines and analyzing human movement.

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