Maximum altitude of a rocket if launched vertically

[karan01]

Homework Statement

The missile has maximum horizontal range of 160km. What is the maximum altitude it can reach if launched vertically?

Homework Equations

v²=u² +2as

The Attempt at a Solution

v=0 (because the velocity is zero when it is not rising anymore)
u=0
a= -9.8 (up is the positive direction
s= the answer, the height

That is how I thought I am supposed to do it...

By the way you guys do a great job on these forums, I lurk here a lot :)

 

[Onamor]

The missile has maximum horizontal range of 160km.

You can extract the information you need from that line. How do you achieve maximum horizontal distance with a projective under gravity?

Also are you sure initial velocity, u, should be zero?

 

[Swap]

apply the formula for calculating the maximum range. From there u will get the Velocity of the projectile.