Question

2
A body is projected at such an angle that the hori-
zontal range is three times the greatest height. The
angle of projection is :-
(AIIMS 1998, DPMT 2000]
(1) 25°
(2) 33°
(3) 42°
41530​

Answer 1

Explanation:

equate this u will get ur ans

u^2sin2theta/ g = u^2 sin ^2 theta / 2g

Answer 2

we know,  

horizontal range = u²sin2\phi /g

maximum height =u²sin²ϕ/2g

A/C to question,

horizontal range =3× maximum height  

u²sin2ϕ/g=3×u²sin²ϕ/2g  

$${ sin2\phi  = 2sin\phi .cos\phi  }$$

2sinϕ.cosϕ=3/2.sin²ϕ

tanϕ=4/3  

ϕ=tan⁻¹(4/3)

Hence,

option (D) is correct answer.