A computer's hard disk is spinning at 90 revolutions per second. Through how many degrees does it travel in a second? In a minute?

1 revolution means 360 degrees because a circle is 360 degrees

90 revolutions means 360 degrees times 90 revolutions=32400 degrees in a second

in a minute, we multiply by 60 because 60 seconds per minute

32400 times 60=1944000 degrees per minute

Dimensional analysis

90 rev / sec x 360 deg / rev = 32400 deg/sec

32400 deg/sec x 60 sec/min =

How many degrees are there in a circle? Answer: 360 degrees

1 revolution = 1 full circle

(360 degrees / 1 revolution) * (90 revolutions / 1 second) = 32,400 degrees / second

same for the next part, just multiply by 60 to get degrees per minute