Q. Old naval ships fired 14 cannon balls from a 240 cannon. It was very important to stop the recoil of the cannon, since otherwise the heavy cannon would go careening across the deck of the ship. In one design, a large spring with spring constant 2.0×104 was placed behind the cannon. The other end of the spring braced against a post that was firmly anchored to the ship's frame.
Q. A 220 g block on a 54.0 cm-long string swings in a circle on a horizontal, frictionless table at 55.0 rpm.What is the speed of the block and tension in the string?