# Angular Acceleration generation help

• pines344
In summary, you are trying to build a set up using a pendulum and a cylinder to generate angular acceleration. You started from basic physics to try to find an answer, but you don't seem to be able to go any further. You need more information about the model you are trying to build.
pines344
Hello,

I am in process of building a set up where i will be using a pendulum to impact a cylinder to generate angular acceleration. I started from basic physics for a answer and found the following method but doesn't seem to go any where from here. Please provide guidance.

Torque = Moment of Inertia X Angular Acceleration
So, Angular Acceleration = Torque/Moment of Inertia
where
Torque = Force x length = mass of pendulum x acceleration due to gravity x length of pendulum
Moment of Inertia = Mass x Lenght^2 = mass of pendulum x length of pendulum^2

Hi and welcome.
Those formulae look ok but you ask where to go from there.
You haven't given any detail about what you want to do and we can't go anywhere without an idea of the set up you are planning.

Are you, perhaps, trying to do the rotational equivalent of linear momentum transfer when one mass collides with another?
The same basic laws apply, so you can say that the total initial angular momentum is equal to the total final momentum and that torque X the time it acts (rotational impulse) equals the change in angular momentum. There are more variables than in the linear case because you need to specify the radii involved, which may be different(?) for the pendulum and the cylinder.
It should all be sort-outable, given a better description of the model.

Hello,

I will try here to better define the complete fixture. I had build this initially to generate the linear acceleration but want to modify it to also generate the angular accelerations.

Pendulum : The rod of the pendulum is around 65 inches tall. One end of the rod is free to rotate whereas the other end has a pendulum where i can add and remove weights. Also i can change the angle of the rod of pendulum to attain angles from 0 degrees to 85 degrees. This was designed in such a way to attain maximum rotational kinetic energy conveyed to the sled to gain maximum linear accelerations.

Sled : Sled which moves on rails has a cylinder on which i will be measuring the angular acceleration. For angular measurements i will have the sled contrained not move on rails. At this point i am not sure about the diameter of the cylinder but i assume it would be approximately 12 inches.

My question was how do i convert the rotational kinetic energy of the pendulum into angular acceleration of the cylinder.

Thanks
Pines344

Not sure if the provided information was sufficient to provide a response. Please let me know if more info is needed.

Thanks
Pines344

Firstly, it is important to understand the concept of angular acceleration and how it relates to torque and moment of inertia. Angular acceleration is the rate of change of angular velocity, and it is caused by a net torque acting on an object. Torque is the rotational equivalent of force, and it is calculated by multiplying the force applied to an object by the distance from the pivot point (or axis of rotation). Moment of inertia, on the other hand, is a measure of an object's resistance to changes in its rotational motion. It depends on the mass and distribution of mass of the object, as well as the distance from the pivot point.

In your set up, the pendulum will provide the force and the cylinder will act as the object with angular acceleration. To generate angular acceleration, you will need to apply a net torque to the cylinder. As you correctly stated, the formula for torque is Torque = Moment of Inertia x Angular Acceleration. So, to calculate the required angular acceleration, you will need to divide the torque by the moment of inertia of the cylinder.

However, it is important to note that the moment of inertia will also depend on the shape and size of the cylinder, not just its mass. So, you will need to consider the moment of inertia of the cylinder in your calculations. Additionally, you will need to ensure that the pendulum is able to provide enough force to generate the desired torque on the cylinder.

I would also recommend conducting some experiments to test your set up and make any necessary adjustments. This will help you better understand the relationship between torque, moment of inertia, and angular acceleration in your specific setup.

I hope this guidance helps and good luck with your project!

## What is Angular Acceleration?

Angular acceleration is the rate of change of angular velocity with respect to time. It measures how quickly an object's angular velocity is changing, similar to how linear acceleration measures how quickly an object's linear velocity is changing.

## How is Angular Acceleration calculated?

Angular acceleration is calculated by dividing the change in angular velocity by the change in time. Its unit is radians per second squared (rad/s^2).

## What factors affect Angular Acceleration?

Angular acceleration is affected by the torque applied to an object and the moment of inertia of the object. The greater the torque or the smaller the moment of inertia, the greater the angular acceleration.

## What is the relationship between Angular Acceleration and Angular Velocity?

The relationship between angular acceleration and angular velocity is similar to the relationship between linear acceleration and linear velocity. Angular acceleration is the rate of change of angular velocity, meaning it measures how quickly the angular velocity is changing at a given moment.

## How is Angular Acceleration used in real life?

Angular acceleration is used in many real-life applications, such as understanding the motion of rotating objects like wheels, gears, and turbines. It is also important in understanding the stability of objects in motion, such as a spinning top or a gyroscope.

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