Question

Two balls are projected horizontally from the top of a building simultaneously with velocities of 12 m s${}^{-1}$ and 15 m s${}^{-1}$ respectively. The ratio of times taken by them to reach the ground is ________.

• A. $4:5$
• B. $1:1$
• C. $5:4$
• D. none of the above

Answer 1

The correct option is B $1:1$

Time of flight $T=\sqrt{\frac{2h}{g}}$

where $h$ is the height of the building

So, time of flight is independent of the horizontal velocity of the balls.

Thus both the balls reach the ground simultaneously.

So, ratio of time of fight $T_1:T_2=1:1$