Find the Angular Acceleration, acceleration and friction force extered

In summary, the question involves a circular disk with a mass of 16 kg and a radius of 595 mm, which has a concentric circular groove of 220-mm radius. A force T of 41 N at an angle of 39° is applied to a cord wrapped around the groove. The problem asks for the angular acceleration, acceleration of its mass center, and the friction force exerted on the disk. Using a free body diagram and the equations of motion, the solution can be found by setting up three equations and solving for the unknown variables. The final solution involves four equations and five unknowns, but the acceleration in the y-direction can be assumed to be 0, so the kinetic or static friction equation can be used
  • #1
Northbysouth
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2

Homework Statement


The circular disk of 595-mm radius has a mass of 16 kg with centroidal radius of gyration = 500 mm and has a concentric circular groove of 220-mm radius cut into it. A steady force T is applied at an angle θ to a cord wrapped around the groove as shown. If T = 41 N, θ = 39°, μs = 0.23, and μk = 0.19, determine the angular acceleration α of the disk, the acceleration a of its mass center G, and the friction force F which the surface exerts on the disk. The angular acceleration α is positive if counterclockwise, negative if clockwise; the acceleration a is positive if to the right, negative if to the left; and the friction force F is positive if to the right, negative if to the left.

I have attached an image of the question

Homework Equations



rs is the smaller radius of 220 mm

rL is the larger radius of 595 mm

I = k2
m

The Attempt at a Solution



I started off by drawing a FBD of the circular disk, in which I included the forces of T, mg, N (normal force) and F (friction force)

ƩFx: max = Tcos(θ) - F

ƩFy: may = Tsin(θ) - mg + N

ƩMG: IGα = Trs - FrL

So, now I have three equations but 5 unknowns: ax, ay, F, N and α. How do I find the other two equations?

EDIT:

I've just realized that ay = 0. So, could I use F = u*N, where u would be the kinetic of static friction, as the fourth equation?
 

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  • #2
Yeah, I jumped the gun a bit.

It looked more complicated than it was. I've solved it now. Thanks
 

Related to Find the Angular Acceleration, acceleration and friction force extered

1. What is angular acceleration?

Angular acceleration is the rate at which an object's angular velocity changes over time. It is measured in radians per second squared (rad/s^2).

2. How is angular acceleration related to linear acceleration?

Angular acceleration and linear acceleration are related through the radius of rotation. The formula is α = a/r, where α is the angular acceleration, a is the linear acceleration, and r is the radius of rotation.

3. What factors affect the angular acceleration of an object?

The angular acceleration of an object is affected by several factors, including the object's mass, the torque applied to the object, and the moment of inertia (a measure of an object's resistance to rotational motion).

4. How does friction force affect angular acceleration?

Friction force can have a significant impact on an object's angular acceleration. If the friction force is greater than the applied torque, the object will experience negative angular acceleration and eventually come to a stop. If the friction force is less than the applied torque, the object will experience positive angular acceleration.

5. Can angular acceleration be negative?

Yes, angular acceleration can be negative. This means that the object is experiencing a decrease in angular velocity, or deceleration. Negative angular acceleration can occur if the torque applied to the object is in the opposite direction to its current angular velocity.

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