Answer:
y = 20 [m]
Explanation:
To solve this type of problem we must use the following equation of kinematics.
[tex]v_{f}^{2} =v_{o}^{2}-2*g*y[/tex]
where:
Vf = final velocity = 0
Vo = initial velocity = 20 [m/s]
g = gravity acceleration = 10 [m/s²]
y = elevation [m]
Now the key to solving this problem is to know that when the stone reaches the maximum height its speed is zero. Therefore the final velocity term is zero.
[tex]0 = (20)^{2}-2*10*y\\20*y=400\\y=20 [m][/tex]
Another important fact is that the sign of gravitational acceleration was taken as negative, since it acts in the opposite direction to the movement of the stone.
