4. The platter of the hard drive of a computer rotates at 7200 rpm (rpm = revolutions per minute = rev/min). What is the angular velocity (rad/s) of the platter? (1 rev=2π rad)

The angular velocity is

Explanation:

Given values:

rotates =  7200 rpm where rpm stands for revolutions per minute.

1 rev = 2 rad,

1 min = 60 second.

Find:

w(Angular Velocity (rad/s)) =?

Solution:

only #2 represents an object at rest on a table.

in #1, there is no normal force due to the table; the object is accelerating downward.

in #3, the vertical forces are not balanced; the object is accelerating downward.

in #4, neither the vertical nor the horizontal forces are balanced. the object is accelerating upwards and to the right.