A projectile A is projected from ground. An observer B running on ground with uniform velocity of magnitude 'v' observes A to move along a straight line. The time of flight of A as measured by B is T. Then the the range R of projectile on ground is

Options

A. `R=vT`
B. `RltvT`
C. `RgtvT`
D. information insufficient to draw inference

Answer

A

Explanation

The horizontal and vertical components of initial velocity of projectile are as shown in figure. Since the observer moving with uniform velocity v sees the projectile moving in straight line Hence `v=ucostheta`
The time of flight as measure by observer B is
`T=(2usintheta)/(g)`
Hence horizontal range of projectile on ground
`R=(ucostheta)T=vT`