Angular Momentum tricky problem

In summary, the conversation discusses a problem involving several variables and the use of equations such as the parallel axis theorem and the relationship between angular and tangential acceleration. The person is struggling with the problem and is seeking help in understanding how to approach similar problems in the future. They are asked to show their calculations in order to receive assistance.
  • #1
lecammm
9
0

Homework Statement


As the picture shows, we are given several variables, but I am near completely lost. I am behind in my course and am trying to catch up as best as I can but this problem is really hard for me


Homework Equations



The equations that I have used are;

parallel axis theorem
angular acceleration = tangential acceleration*radius

The Attempt at a Solution


I know that this solution will be completely wrong as I haven't utilised the frictional torque, nor the angle.

So, by applying the parallel axis theorem for the mass moment of inertia;

I0 = I + mr^2
I(slender bar) = 1/12 * m * L^2
∴ I0 = 1/12 * m * L^2 + mr^2

then used the fact that:

ƩM0 = I0:

and therefore:

mgb = I0 * angular acceleration:
where b is the distance from the COM

however, as assumed, this gave the wrong answer, I'm really stuck with it and I want to know how I can do it for problems to come. Thanks! :D
 

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  • #2
You need to show your calculations.

Your equation for the sum of the moments = I0 is incomplete.

How are we to know what you've done if you don't provide your work?
 

1. What is angular momentum?

Angular momentum is a physical quantity that measures the amount of rotational motion an object has. It is a vector quantity that takes into account both the mass and velocity of an object as well as its distance from a fixed axis of rotation.

2. How is angular momentum calculated?

Angular momentum is calculated by multiplying an object's moment of inertia, or resistance to rotational motion, by its angular velocity. The formula is L = Iω, where L is angular momentum, I is moment of inertia, and ω is angular velocity.

3. What is the conservation of angular momentum?

The conservation of angular momentum states that in a closed system, the total angular momentum remains constant. This means that if there are no external torques acting on a system, the angular momentum before an event will be equal to the angular momentum after the event.

4. How is angular momentum related to torque?

Torque and angular momentum are related through Newton's second law for rotational motion. Torque is the rate of change of angular momentum, meaning that an applied torque will cause a change in the angular momentum of an object.

5. What is an example of a tricky angular momentum problem?

An example of a tricky angular momentum problem could be a situation where an object is rotating on an axis and then a second object is added to the system. The problem may involve determining the final angular momentum and angular velocity of the system, taking into account the conservation of angular momentum and any external torques acting on the system.

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