A tetherball of mass m is attached to the ceiling by a cord of length L. Someone gives it a push, causing it to swing around in a horizontal circle with a constant speed v, so that the cord forms an angle ̘ from vertical (see figure). If m = 0.425 kg, L = 2.15 m and ̘ = 25.0°, find a. the magnitude of the tension in the cord. b. the speed v.