4.29 A bullet fired at an angle of 30° with the horizontal hits the ground 3.0 km away. By adjusting its angle of projection, can one hope to hit a target 5.0 km away? Assume the muzzle speed to be fixed, and neglect air resistance.

 

NEETprep Answer:
Given,
R=3km
θ=300
g=9.8m/s2
Weknowthat,
R=u2sin2θg
3=u2gsin600
u2g=23......1
If,θ=450
Rmax=u2g......2
Oncomparingequation1and2,weget,
Rmax=23=2×1.732=3.46km
Therefore,thereisnowaywecanhitthetarget.