Question

2) The rotation speed of an HDD (a magnetic hard drive disk) is 4500 rmp. Its radius is roughly 5 cm. What is the tangential velocity of the disk at the edge? What is the acceleration of the disk at the edge?

Answer 1

As 1 RPM = 2/60 rad / sec

So 4500 RPM = 4500*2/60 = 471.238 rad/sec

Now as v = r* = 5*10^(-2)*471.238 = 23.56 m/sec

So tangential velocity = 23.56 m/sec. Ans.

Now radial acceleration a = v^2/r

Here v is radial Velocity in m/s = 23.56 m/sec.

Radius in meters = 0.05 meters.

So radial acceleration a= 23.56^2/0.05 = 11101.47 m/s^2

and tangential acceleration = 0.