The speed of a moving bullet can be determined by allowing the bullet to pass through two rotating paper disks mounted a distance
87 cm apart on the same axle. from the
angular displacement of 21.6◦
of the two bullet holes in the disks and the rotational speed
537 rev/min of the disks, we can determine
the speed of the bullet.
what is the speed of the bullet?
answer in units of m/s.

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