Question

The initial speed of a projectile fired from ground is $u$ At the highest point during its motion, the speed of projectile is $\frac{\sqrt{3}}{2} u$ The time of flight of the projectile is :

• A. $\frac{2 u }{ g }$
• B. $\frac{ u }{2 g }$
• C. $\frac{ u }{ g }$
• D. $\frac{\sqrt{3} u}{g}$

Answer 1

Answer: (C)

$\frac{ u }{ g }$

Answer 2

$u\ cosθ=\frac{\sqrt{3}​u}{2}$​
$⇒cosθ=\frac{\sqrt{3}}{2}$
$⇒θ=30^∘$
$T=\frac{2usin30^∘}{g}​=\frac{u}{g}$​
Correct answer is option (b)