Question

A grasshopper can jump a maximum distance $1.6m$. It spends negligible time on the ground. How far can it go in $10s$?

• A. $5\sqrt{2}m$
• B. $10\sqrt{2}m$
• C. $20\sqrt{2}m$
• D. $40\sqrt{2}m$

Answer 1

Answer: (C)

$20\sqrt{2}m$

Here angle of projection $={45}^{\circ }$
$R_{max}=1.6=\frac{u^2}{g}=\frac{u^2}{10}$ or $u=4m{s}^{-1}$.
Hence, the distance covered in $10s$ is horizontal $speed\times time=u\cos {45}^{\circ }\times time$
$=4\times \frac{1}{\sqrt{2}}\times 10=20\sqrt{2}m$.