When the play button is pressed, a CD accelerates uniformly from rest to 430 rev/min in 4.0 revolutions. If the CD has a radius of 7.0 cm and a mass of 17 g , what is the torque exerted on it?

The net torque exerted on CD is .

Explanation:

As CD is acceleration uniformly, the following equation of motion can be used to determine the angular acceleration:

Where:

- Initial angular speed, measured in revolutions per minute.

- Final angular speed, measured in revolutions per minute.

- Angular acceleration, measured in revolution per square minute.

- Change in angular position, measured in revolutions.

The angular acceleration is cleared and calculated:

Given that , and , the angular acceleration is:

The angular accelaration measured in radians per square second is:

Net torque experimented by the CD during its accleration is equal to the product of its moment of inertia with respect to its axis of rotation and angular acceleration:

Where:

- Moment of inertia, measured in .

- Angular acceleration, measured in radians per square second.

In addition, a CD has a form of a uniform disk, whose moment of inertia is:

Where:

- Mass of the CD, measured in kilograms.

- Radius of the CD, measured in meters.

If and , then:

Now, the net torque exerted on CD is:

The net torque exerted on CD is .

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

molecules are free to separate from each other and will take on the shape of the container. molecules move completely at random and high speeds. they vibrate in a fixed position and do not move around much. molecules expand to the edge of their container.