question_answer

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 to hit the ground?

A)  \[\sqrt{2}\,s\]                  

B)  2s

C)  \[\sqrt{3}\,s\]                  

D)  3 s

Correct Answer: B

Solution :

                 The time taken to hit the ground is given by \[T=\sqrt{\frac{2H}{g}}=\sqrt{\frac{2\times 19.6}{9.8}}=2s\]