1. A stone of mass 0.5 kg is projected vertically upwards with an initial velocity of 4.0ms^-1. What is its kinetic energy when it reaches a height of 0.5m?
2. http://i48.tinypic.com/iyj0a9.png (both questions)
I couldn't load the Physics Help Forums website. Hope posting in here is just as fine, since it says in the description 'chemistry and physics'.