A projectile goes farthest from the earth when the angle of projection is:
0o
45o
90o
180o
In vertical direction,ui=usinθ, uf=0uf2−ui2=−2gs0−u2sin2θ=−2gss=u2sin2θ2gwhere s is the maximum height. For s to be maximum, sinθ should be maximum, i. e.,θ = 90°.