Starting from rest, a disk rotates about its central axis with constant angular acceleration. in 5.0 s, it rotates 25 rad. during that time, what are the magnitudes of:
(a) the angular acceleration,
(b) what is the instantaneous angular velocity of the disk at the end of the 5.0 s?
(c) the average angular velocity for first 5 s?
(d) with the angular acceleration unchanged, through what additional angle will the disk turn during the next 5.0 s?

By what primary heat transfer mechanism does the sun warm the earth?

Amerry-go-round of radius r, shown in the figure, is rotating at constant angular speed. the friction in its bearings is so small that it can be ignored. a sandbag of mass m is dropped onto the merry-go-round, at a position designated by r. the sandbag does not slip or roll upon contact with the merry-go-round. how would you rank the following different combinations of m and r on the basis of the angular speed of the merry-go-round after the sandbag "sticks" to the merry-go-round from largest to smallest. a) m = 10kg, r = 0.25r b) m = 20kg, r = 0.25r c) m = 10kg, r = 0.50r d) m = 10kg, r = 1.0r e) m = 15kg, r = 0.75r f) m = 40kg, r = 0.25r

Why does a smaller car get better gas mileage than a bigger one?