Question

A projectile is thrown with a speed $v$ at an angle $\theta$ with the vertical. Its average velocity between the instants it crosses half the maximum height is

• A. $vsin\theta$, horizontal and in the plane of projection
• B. $vcos\theta$, horizontal and in the plane of projection
• C. $2vsin\theta$, horizontal and perpendicular to the plane of projection
• D. $2vcos\theta$, vertical and in the plane of projection.

Answer 1

The correct option is A $vsin\theta$, horizontal and in the plane of projection

Between the instances where it crosses half the maximum height, it spends equal amount of time with positive and negative velocity (vertical component).Hence average of vertical component $=0$.
Horizontal component is a constant and is equal to $vsin\theta$. Hence average velocity = horizontal component average = $vsin\theta$.