Question

how & when is range(r) = 2h (max height) for a projectile motion?

Answer 1

There is a formula RtanA = 4H
where R is the range, A is the angle of projection and H is the max height.

So if (according to your question) R=2H

Then 2HtanA = 4H
=> tanA=2
=> A=tan^-1(2) = (approx.) 63°

So if the angle of projection is 63° then the range will be twice the max. height.


HOPE IT HELPS..... :-)