Question

A CD is spinning on a CD player. In 220 radians, the cd has reached an angular speed of 92 r a d s by accelerating with a constant acceleration of 14 r a d s 2 . What was the initial angular speed of the CD

Answer 1

The initial angular speed is
`w_i = 48 \ rad/s`

Step-by-step explanation:

From the question we are told that

The angular displacement is
`\theta = 220 \ rad`

The angular speed is
`w_f = 92 \ rad/s`

The acceleration is
`\alpha = 14 \ rad/s^2`

Generally the initial angular speed can be evaluated as

`w_f ^2 = w_i ^2 + 2 * \alpha * \theta`

=>
`w_i ^2 = w_f ^2 - 2 * \alpha * \theta`

substituting values

=>
`w_i ^2 = 92 ^2 - 2 * 14 * 220`

=>
`w_i ^2 = 2304`

=>
`w_i = 48 \ rad/s`