Practice question
Question
A ball is thrown horizontally at 5m/s from a height of 20m. What is its horizontal range? (Take g\=10m/s2)
Explanation
Time to fall: h=12gt2⇒20=12×10×t2⇒20=5t2⇒t2=4⇒t=2s. As per NCERT Chapter 3, equations v=u+at, s=ut+½at², v²=u²+2as describe uniformly accelerated motion. Applying correct signs and units gives 10 m as the result, so option D is correct.