The angle of projection of a particle is measured from the vertical axis as ϕ and the maximum height reached by the particle is hm. Here hm as function of ϕ can be presented as
(A)(see structure)
(B)(see structure)
(C)(see structure)✓ Correct
(D)(see structure)
Answer: (C)
Solution
With the projection angle ϕ measured from the vertical, the angle above the horizontal is 90∘−ϕ, so the vertical component of the launch speed is ucosϕ. The maximum height reached is
hm=2g(ucosϕ)2=2gu2cos2ϕ.
Thus hm is greatest at ϕ=0, a purely vertical throw, and falls to zero at ϕ=90∘, a horizontal throw. Since dϕdhm=−2gu2sin2ϕ vanishes at ϕ=0, the curve leaves its maximum with a horizontal tangent and then decreases to zero at 90∘. The graph that represents hm(ϕ) is the one starting at its maximum value with a flat tangent at ϕ=0 and decreasing to zero at ϕ=90∘.
JEE Main · 2025 · 03 Apr 2025 · Shift 1 · Single correct option