Question

A ball is projected horizontally with a velocity of $5 \,m/s$ from the top of a building $19.6\, m$ high. How long will the ball take of hit the ground ?

• A. $\sqrt{2}\,s$
• B. $2\, s$
• C. $\sqrt{3}\,s$
• D. $3\, s$

Answer 1

Answer: (B)

$2\, s$

Answer 2

The time taken to hit the ground is given by

$T=\sqrt{\frac{2 H}{g}}$
$=\sqrt{\frac{2 \times 19.6}{9.8}}=2 \,s$