When air resistance is taken into account while dealing with the motion of the projectile which of the following properties of the projectile, shows an increases?

Options

A. range
B. maximum height
C. speed at which it strikes the ground
D. the angle with horizontal at which the projectile strikes the ground

Answer

D

Explanation

Let the effect of air resistance give an extra acceleration
Upward motion : Air resistance downwards `overset(-)a=-a_(1)hati+(-g-a_(2))hatj`
Downward motion : Air resistance upwards
`overset(-)=-a_(1)hati+(-g+a_(2))hatj`
A to P (A) `0^(2)=u_(y)^(2)+2(-g-a_(2))h rArr h=(u_(y)^(2))/(2(g+a_(2)) ["This is less than "(u_(y)^(2))/(2g)]`
Range decreases, as air resistance oppose horizontal motion.
(C) As energy is lost, KE (and hence speed) is less when it lands.