If you are going to throw a 1kg ball vertically upward and reach a maximum height of 18m. A)How much energy is needed? B)What should be the initial speed of the ball? My solution: mgh=1/2mv^2 v=√2gh v=√2(9.8)(18) v=18.78m/s In getting the energy I derived the work energy theorem 2w=vo^2 2w=18.78^2 w=176.34 joules I'm not sure if my answer is correct so I would be extremely grateful if someone could check it. Thanks.