Ablock starts at rest and slides down a frictionless track. it leaves the track horizontally, flies through the air, and subsequently strikes the ground. b b b b b b b b b b b b 472 g 4.1 m 1.8 m x v what is the speed of the block when it leaves the track? the acceleration of gravity is 9.81 m/s 2 . answer in units of m/s