Question

An audio compact disk (CD) has a playing time of 55 minutes. When the music starts, the CD is
rotating at an angular speed of 480 revolutions per minute (rpm) and during the playback the
rotation slows down. The average angular acceleration of the CD is a = -4.0 rev/min . Find the
angular speed at which the CD is rotating at the end of the music. Express your answer both in
rev/min and also in rad/s.

Select one:
27.2 rad/s
220 rad/s
120 rad/s
260 rad/s
22 rad/s

Answer 1

Answer:

See below

Explanation:

-4 rev / min^2 * 55 min =  - 220 rev/ min

480 - 220 = 260 rev/min at end

2pi radians /rev * 260 rev/min  = 1633.6 Radians/min

Answer 2

At the end of the music, the angular speed of the C.D. would be (d) 260 rev/minute and 1633.6 rad/minute

To calculate angular speed following information is given in the question:

• The angular speed (ω) of the C.D. at starting = 480 revolutions/minute

• The playing time (t) of the C.D. is = 55 minutes

• The angular acceleration (α) of the C.D. = -4 rev/$min^{-2}$
• Angular speed of the C.D. at the end of the music will be = α*t
• Angular speed of the C.D. at the end of the music will be = 4 rev/$min^{-2}$ *55 min = -220 rev/min
• At the end of the music angular speed = 480-220 rev/min = 260 rev/min

• Value of angular speed in rad/sec = 2π radians/rev*260 rev/min = 1633.6 Radians/min

Hence, option (d) is correct which states that the angular speed is 260 rev/min and 1633.6 radians/min.

To know more about angular speed, refer:

https://brainly.com/question/6860269

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