Question

If for a given angle of projection, the horizontal range is doubled, the time of flight becomes

• A. 4 times
• B. 2 times
• C. $\sqrt{2}$times
• D. $1/\sqrt{2}$times

Answer 1

Answer: (C)

$\sqrt{2}$times

Answer 2

$R = \frac{u^{2}\sin 2\theta}{g}$and $T = \frac{2u\sin\theta}{g}$

$\therefore R \propto u^{2}$ and $T \propto u$ (If $\theta$and g are constant).

In the given condition to make range double, velocity must be increased upto $\sqrt{2}$times that of previous value. So automatically time of flight will becomes $\sqrt{2}$times.