CE and DF are two walls of equal height (20 meter) from which two particles A and B or same mass are projected as shown in the figure. A is projected horizontally towards left while B is projected at an angle `37^(@)` (with horizontal towards left) with velocity `15 m//sec`. If A always sees B to be moving perpendicular to EF then the range of A on ground is

Options

A. 24 m
B. 30 m
C. 26 m
D. 28 m

Answer

A

Explanation

From given conditions
`V_(A)=V_(B) cos 37_(0) = 15.(4)/(5) =12 m//sec`
`:.` time of flight of `A(t) = sqrt((2 xx 20)/(10))=20 sec`
`rArr` Range `=V_(A) t = 24 m`.