Join the Most Relevant JEE Main 2025 Test Series & get 99+ percentile! Join Now
Search any question & find its solution
Question: Answered & Verified by Expert
A particle is projected vertically upwards. If it has to stay above the ground for 12 seconds, then
MathematicsBasic of MathematicsWBJEEWBJEE 2020
Options:
  • A velocity of projection is $192 \mathrm{ft} / \mathrm{sec}$
  • B greatest height attained is $600 \mathrm{ft}$
  • C velocity of projection is $196 \mathrm{ft} / \mathrm{sec}$
  • D greatest height attained is $576 \mathrm{ft}$
Solution:
1008 Upvotes Verified Answer
The correct answers are: velocity of projection is $192 \mathrm{ft} / \mathrm{sec}$, greatest height attained is $576 \mathrm{ft}$
Hint:
$V=u-g t$ at $t=6$
$u-g t=0$
$\Rightarrow u=6 g=192 f t /$ sec $\quad\left(g=32 f t / \sec ^{2}\right) \ldots \ldots . .(\mathrm{i})$
$x=u t=\frac{1}{2} g t^{2}$
$=192.6-\frac{1}{2} 32.6^{2}$
$=576 \mathrm{ft}$

Looking for more such questions to practice?

Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.