# What is the torque of a cd after accelerating to 500 rev/min in 3.0 revolutions?

• ryty
In summary, the problem involves a CD accelerating uniformly from rest to 500 rev/min in 3.0 revolutions. It has a radius of 5.5 cm and a mass of 20 g. To find the torque, we can use the equation \omega^{2}=2\alpha s, where s=2\pi r * 3 and 500 rev/min is equal to 4770 rad/sec.
ryty

## Homework Statement

When play is pressed, a cd accelerates uniformly from rest to 500 rev/min in 3.0 revolutions. If the Cd has a radius of 5.5 cm, and a mass of 20 g, what is the torque?

## Homework Equations

not sure, this is my problem. i think its torque=angular acceleration*inertia. but i don't know how to turn "500 rpm in 3.0 revolutions" into angular acceleeration

## The Attempt at a Solution

nothing, i don't how to make the equations work

You have your analogy from linear kinematics equations to rotational motion equations.

a = delta v / delta t

So the same is true for rotational acceleration, and change in rotational velocity

but how does torque fit into this equation?

You can use: $$\omega^{2}=2\alpha s$$ , where $$s=2\pi r * 3$$ (3 times the circumference)

and 500 $$rev/min=4770 rad/sec$$

## What is torque in circular motion?

Torque in circular motion is the measure of the force that causes an object to rotate around an axis. It is a vector quantity that is dependent on the magnitude and direction of the force, as well as the distance between the force and the axis of rotation.

## How is torque calculated?

Torque is calculated by multiplying the force applied to an object by the distance from the axis of rotation to the point where the force is applied. The formula for torque is T = F x r, where T is torque, F is force, and r is the distance from the axis of rotation.

## What is the unit of measurement for torque?

The unit of measurement for torque is the Newton-meter (Nm) in the metric system, and the foot-pound (ft-lb) in the imperial system. However, torque can also be expressed in other units such as joules (J) or pound-force feet (lbf-ft).

## How does torque affect circular motion?

Torque is responsible for causing rotational motion in objects. The greater the torque applied, the faster the object will rotate. This means that torque has a direct effect on the speed of an object in circular motion.

## What are some real-life examples of torque in circular motion?

Some real-life examples of torque in circular motion include turning a doorknob, using a wrench to tighten a bolt, and spinning a top. In each of these examples, a force is applied at a distance from the axis of rotation, causing the object to rotate.

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