Question

A particle is thrown vertically up with a velocity of $ 100 \,ms^{-1} $ . What will be the time taken by the body to reach the ground? Assume $ g = 10\, N $ .

• A. $ 5 \,s $
• B. $ 10 \,s $
• C. $ 15 \,s $
• D. $ 20 \,s $

Answer 1

Answer: (D)

At maximum height, $v = 0$
From $v=u-gt$
$\Rightarrow t=\frac{u}{g}$
$=\frac{100}{10}$
$=10\,s$
Time of ascent = time of descent $=10\,s$
$\therefore $ Flight time $=10+10=20\,s$