Uniform circular motion question

AI Thread Summary
The discussion revolves around analyzing the forces acting on an object in uniform circular motion at various positions. The user seeks validation for their diagrams and equations regarding the net forces and tensions at four specific points in the circular path. Key points include the relationships between tension and weight, with conditions where tension equals or exceeds weight. The conversation also addresses the nature of acceleration in circular motion, clarifying that while angular velocity remains constant, the acceleration components depend on the object's position relative to the center. Overall, the inquiry emphasizes understanding the dynamics of forces in a circular motion context.
Miike012
Messages
1,009
Reaction score
0
Please look at the picture...
It is of a blue object in four locations that is swung around with a rope ( red line ) in a circle with constant velocity...

I wanted to know if my diagrams are correct for each separate location... and I was hoping someone could check my work below to tell me if it is correct...

1. ƩFx = 0; ƩFy = -T - W = (m)(a) and T = W

2. ƩFx = -T - W = (m)(a) ƩFy = 0 and T> W

3. ƩFx = 0; ƩFy = +T - W = (m)(a) and T>W

4. ƩFx = T - W = (m)(a) ƩFy = 0 and T>W
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    15.2 KB · Views: 438
Physics news on Phys.org
And for an object somewhere other than the first four points... would the objects have both nonzero acceleration for ƩFx and ƩFy ?
 

Attachments

  • 22.jpg
    22.jpg
    12.2 KB · Views: 423
Is the angular velocity constant? If so, then there will be no acceleration "around" the loop. The idea is that the object has centripital(sp?) acceleration towards the center. As the thing moves around the circle, the reference frame changes along with it. If acceleration is always pointing in the positive y (or whatever you called the center), then it can't have separate components can it?
 
I never said acceleration was around the circle... if you noticed I always said acceleration points to the sum of the vectors which is in the direction of Tension force...
I added another picture with a coordinate axis... I am not sure if it will make a diff,,,?

And velocity is constant, I mentioned uniform circular motion...
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    15.9 KB · Views: 432
Last edited:
I was referring to this:

Miike012 said:
And for an object somewhere other than the first four points... would the objects have both nonzero acceleration for ƩFx and ƩFy ?

Which the answer would have been no if you were using the coordinate system where the center point is positive y regardless of where the object is around the circle. (A polar type grid).

If you use the grid in your image then yes. Acceleration will have component vectors for the times when the object is not at 0, pi/2, pi, etc. which would have to be summed in your forces.
 
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top