When a ball is thrown up vertically with velocity v0 . It reaches a maximum height of h . If one wishes to triple the maximum height then the ball should be thrown with velocity

Here x'=(v'v)2x or 3h=(v'v0)2h ∴v'=v03             As v2=u2+2as      So 0+v02+2(−g)h    (or)   v0=2gh             Or  v0αh    When h'=3h then v0'=h'=3h  ∴v0'v0=3hh=3   (or)  v0'=3v0