How Does Doubling Initial Height Affect Projectile Range?

[pxp004]

What happens to range if the initial height is doubled. Say if something is shot at 2 ft and then its shot at 4 ft high, what happens to range? I know that its conservation of energy. I just have no idea how to come up with the right answer

 

[Flipmeister]

Plain kinematics can explain projectile range. A bullet shot horizontally will take a certain time to fall from height 2 ft to hit the ground. There's no initial vertical velocity so that time only depends on your acceleration. Use that time to find how far it goes.