Finding direction of angular momentum of system~

In summary, the conversation discusses a system consisting of a vertical rod attached to a spinning disk, with a piece of the disk crumbling off and rising vertically. The direction of the angular momentum of the system is asked to vary as the chip flies upward, and it is clarified that the magnitude decreases but the direction is not specified. The second question asks about the effect of the disk's spin on the system's angular momentum, but it is unclear what specific change is being considered. The concept of adding angular momentum vectors of a system's components is also mentioned.
  • #1
jcruise322
36
1

Homework Statement


A rod that is fixed to a vertical wall is attached through the middle of a solid disk. A piece of the disk crumbles off when the disk is spinning and rises vertically. The system is the chip and the spinning disk.
Assume no friction.

A. How does the direction of the angular momentum of the system vary as the chip flies upward?

B. How does the direction of the disk's spin affect the systems angular momentum? [/B]

Homework Equations


Li=Lf
Rxmv=I*w[/B]

The Attempt at a Solution



A. Since the chip's speed decreases, I would wager that the system "varies" by decreasing?[/B]

B. I have no idea how the disks spin contributes to the system angular momentum. I know the direction of the angular momentum vector for the disk is in the same direction of its angular velocity (horizontally in the picture). How do I find the direction and shape of a angular momentum vector for a system though?
What if the disk were spinning different directions? I never thought that would affect the angular momentum of the system...
Anyway, I would appreciate opinions on the issue.
 
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  • #2
The question asks how the direction of the angular momentum changes. You stated, correctly, that the magnitude decreases, but that is not what was asked.
I'm not at all sure what B is asking. There is no description of any proposed change to the direction of the disk's spin. Are we to consider the rod not being horizontal? If so, the chip will not go vertically, which does make matters more interesting. Or did they mean the sense of the spin?
To answer your question about angular momentum of a system, just add the angular momentum vectors of its components.
 

Related to Finding direction of angular momentum of system~

1. What is angular momentum?

Angular momentum is a measure of an object's tendency to continue rotating around an axis. It is defined as the product of an object's moment of inertia and its angular velocity.

2. How do you calculate the angular momentum of a system?

The angular momentum of a system can be calculated by multiplying the moment of inertia of the system by its angular velocity. The moment of inertia is a measure of an object's resistance to changes in its rotation, and can be calculated by summing the products of each mass element in the system and its distance from the axis of rotation.

3. How do you determine the direction of angular momentum in a system?

The direction of angular momentum in a system is determined by the right-hand rule. If the fingers of your right hand curl in the direction of the object's angular velocity, the thumb points in the direction of the angular momentum.

4. What factors affect the angular momentum of a system?

The angular momentum of a system can be affected by changes in its moment of inertia, angular velocity, or both. Changes in the distribution of mass within the system or external forces acting on the system can also affect its angular momentum.

5. How is angular momentum conserved in a system?

The law of conservation of angular momentum states that the total angular momentum of a system remains constant when there is no net external torque acting on the system. In other words, the angular momentum of a system cannot be created or destroyed, but can only be transferred between different parts of the system.

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