Question

Find the velocity of a projectile missile which has a range of 150m and time flight 3s.

Answer 1

Here , Range is maximum range of missile.
therefore, R=u²/g..becuz range is maximum at angle of projection =45°.and sin2×45=sin90=1
now, T at angle 45°=2usin45/g=2u/√2g. = √2u/g
now, R/T=u²/g÷√2u/g=u/√2
then,u=√2×R/T=√2×150/3=50√2m/s
or
70.5m/s