. A rock of mass 0.5 kg is launched straight up. A constant upward force of 405 N acted on the rock while it moved 25 cm upward starting from rest. Ignore air resistance. a. Find the launce speed using the work-energy theorem [use g = 10 m/s2). b. Using energy ideas, find the maximum height above the launch point (25 cm) the rock will reach.​

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