Physics Two Dimensional Motion Question 182

Question: For a stone thrown from a lower of unknown height, the maximum range for a projection speed of 10 m/s is obtained for a projection angle of $ 30{}^\circ . $ The corresponding distance between the foot of the lower and the point of landing of the stone is

Options:

A) $ 10m $ B) $ 20m $ C) $ ( \text{20/}\sqrt{3} )\text{ m}!!!! $ D)$ ( 10/\sqrt{3} )\text{ m} $

Show Answer

Answer:

Correct Answer: D

Solution:

[d] $ \tan \theta =\frac{{{u^{2}}}{\text{Rg}} $

$ \Rightarrow \text{R},,\text{=}\frac{{{u^{2}}}{g\tan \theta }=\frac{100}{10\times \sqrt{3}}=\frac{10}{\sqrt{3}}\text{ m} $