A boy throws a ball into air at 45° from the horizontal to land it on a roof of a building of height H. If the ball attains maximum height in 2 s and…
JEE Main 2026 — Physics Mechanics
2026mcqmedium
A boy throws a ball into air at 45∘ from the horizontal to land it on a roof of a building of height H. If the ball attains maximum height in 2 s and lands on the building in 3 s after launch, then value of H is ____ m.
(g=10m/s2)
Official previous-year question
Held on 24 Jan 2026 · Verified 6 Jul 2026.
Options
A
15
B
20
C
25
D
10
Did you get this right?
Sign in to track your attempts and accuracy.
Solution
For projectile motion at 45°, vertical component of initial velocity:
v0y=v0sin45°=2v0
Maximum height occurs at t=2 s when vy=0:
0=v0y−gt
⇒v0y=10×2=20 m/s
Thus 2v0=20, so v0=202 m/s
Height at landing time t=3 s:
H=v0yt−21gt2=20×3−21×10×9
=60−45=15 m
Your note
Sign in to keep a private note on this question. Nothing you write is ever public.