Physics
posted by Sev .
Jo student undertakes a unique experiment with his calculator. He goes to the school roof that is 18.0 m above the ground. He throws the poor calculator upward with a velocity of 42 m/s. Assume that the calculator goes straight up and just misses the roof on its way to the ground.
Calculate the velocity with which the calculator will hit the ground.

For an easy solution, use conservation of energy.
Vo = 42 m/s
Vf = final velocity
M ='mass
H ='rooftop height
MgH + (M/2)Vo^2 = (M/2)Vf^2
Cancel out the M and solve for Vf
Vf^2 = Vo^2 + 2 g H