Question

Two projectiles are fired from the same point with the same speed at angles of projection 60${}^{\circ }$ and 30${}^{\circ }$ respectively. Which one of the following is true?

• A. Their range will be the same.
• B. Their maximum height will be the same.
• C. Their velocity at the highest point will be the same.
• D. Their time of flight will be the same.

Answer 1

Answer: (A)

Their range will be the same.

Given parameters are: ${\theta }_1={60}^0$

And ${\theta }_2={30}^0$.

The horizontal range is the same when the angle of projection is $\theta$ or $({90}^0-\theta )$.

In other ways,

For this projectile motion,

${\theta }_1+{\theta }_2={90}^0$

According to the projectile motion law, both projectiles will have the same speed and horizontal range, due to having complementary angles of projectile motion.

Thus their range will be the same, but maximum height, the velocity at the top, as well as the time of flights, will all be different.

Option A is correct.