If the cd rotates clockwise at 500 rpm (revolutions per minute) while the last song is playing, and then spins down to zero angular speed in 2.60 s with constant angular acceleration, what is α, the magnitude of the angular acceleration of the cd, as it spins to a stop? express your answer in radians per second squared

The solution for this problem is:

500 revolution per minute = 8.33rev /s = 2π*8.33 rad /s = 52.36 rad /s 

Angular velocity ω = 2π N

Angular acceleration α= (ω2 - ω1) /t

ω2 = 0

α = - ω1/t = -2π N /t

N = 500 rpm = 8.33 r p s.

α = -2π 8.33 /2.6 =- 20 rad/s^2

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle