If a stone is thrown upward at 20.5 m/s, what will be its velocity at a height of 12 meters?
Kinetic energy at start = (1/2)m(20.5)^2
Kinetic energy at 12 meters = (1/2) m v^2
so
(1/2) m v^2 = (1/2) m (20.5)^2 - m g (12)
Kinetic energy at 12 meters = (1/2) m v^2
so
(1/2) m v^2 = (1/2) m (20.5)^2 - m g (12)