An optical disk drive in your computer can spin a disk up to 10,000 rpm (about 1045 rad/s ). if a particular disk is spun at 470.2 rad/s while it is being read, and then is allowed to come to rest over 0.569 seconds , what is the magnitude of the average angular acceleration of the disk?

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

Thermal radiation gets its name because

How many astronauts have walked on the moon?