Question

A particle is projected from a point A with a velocity v at an angle q (upward) to the horizontal. At a certain point B, it moves at right angle to its initial direction. It follows that

• A. Velocity of the particle at B is v
• B. Velocity of the particle at B is v cotq.
• C. Velocity of the particle at B is v tan q.
• D. The time of flight from A to B is $\frac{v}{gsin\theta}$.

Answer 1

Answer: (D)

The time of flight from A to B is $\frac{v}{gsin\theta}$.

Answer 2

$\overrightarrow{v} = \overrightarrow{u} + \overrightarrow{a}t$considering along the line AC

0 = v - g sin qt

̃ t = $\frac{v}{g\sin\theta}$

Now consider along the line CB

v¢ = 0 + g cos q $\frac{v}{g\sin\theta} = v\cot\theta$,

Hence, (4) is correct