Question

(II) The platter of the hard drive of a computer rotates at 7200 rpm (rpm = revolutions per minute = rev/min). (a) What is the angular velocity (rad/s) of the platter? (b) If the reading head of the drive is located 3.00 cm from the rotation axis, what is the linear speed of the point on the platter just below it? (c) If a single bit requires 0.50 m of length along the direction of motion, how many bits per second can the writing head write when it is 3.00 cm from the axis?

Answer 1

Answer:

Explanation:

Given:

Angular velocity, w = 7200 rpm

Radius, r = 3 cm

= 0.03 m

1 bit = 0.5 × 10^-6 m

A.

1 rev = 2pi rad

7200 rev/min × 2pi rad/1 rev × 1 min/60 sec

= 753.98 rad/s

B.

Linear velocity, v = r × w

= 0.03 × 753.98

= 22.62 m/s

C.

1 bit = 0.5 × 10^-6 m

Velocity = 22.62 m/s

1 bit/0.5 × 10^-6 m × 22.62 m/s

= 4.524 × 10^7 bits/s