Question

If a rock is thrown upwards from level ground, and its max height is equal to its horizontal range, R, what angle was the rock thrown?

Answer 1

my diagram is;



My current equations are;
\[v _{y} = 0, \Delta _{y}=\frac{ 1 }{ 2 }R\]

So, using,\[\Delta _{y}=v _{o}t+\frac{ 1 }{ 2 }at ^{2}\]
I get;
\[y _{\max}=v _{oy}\frac{ 1 }{ 2 }t+\frac{ 1 }{ 2 }a \frac{ 1 }{ 2 }t ^{2}\]
Becasue
\[\Delta _{y} = \frac{ 1 }{ 2 }R\]