Q. An arrow is shot into air. Its range is $200\ m$ and its time of flight is $5s$. If $g = 10m/s^{2}$, then the horizontal component of velocity of the arrow is
A) $12.5\ m/s$
B) $25\ m/s$
C) $31.25\ m/s$
D) $40\ m/s$
Explanation
(d) $Range\ = \frac{u^{2}\sin{2\theta}}{g} = 200\ m$
$\Rightarrow \frac{u^{2}(2\sin{\theta\cos\theta})}{g} = 200\ m$ ...(i)
$Time\ of\ flight = \frac{2u\sin\theta}{g} = 5s$ ...(ii)
From equations (i) and (ii)
$u\cos\theta = 40\ m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.