Question

Consider projectile motion over level ground with negligible air resistance. The launch angle is greater than 0 degrees and less than 90 degrees. When is the velocity a maximum?

At the beginning of the motion. True or false

At the end of the motion. True or false

At the midpoint of the motion. true or false

At the highest point above the ground. True or false

Answer 1

At the beginning of the projectile motion: True

At the end of the motion. True

At the midpoint of the motion. false

At the highest point above the ground. false

Step-by-step explanation:

We are taking the absolute value of the magnitude of the velocity v. Direction doesn't matter.

Vx = V Cos θ = constant.

Vy = V Sin θ - g t.

So Vy reduces as the projectile goes higher. It's minimum & equal to zero at the maximum height position. Vy starts to increase in magnitude as the projectile falls. At the point of touching the ground, at the end of the motion, the magnitude velocity is equal to the initial velocity at time zero.

Answer 2

Answer: The velocity is a maximum at the beginning of the motion.

Explanation: In projectile motion over level ground with negligible air resistance, the vertical component of the velocity decreases due to the effect of gravity while the horizontal component of the velocity remains constant. At the beginning of the motion (when the projectile is launched), the vertical component of the velocity is at its maximum because there is no vertical displacement yet, and gravity has not started to significantly affect the motion.

As the projectile continues its trajectory, the vertical component of the velocity decreases until it becomes zero at the highest point above the ground. At this point, the projectile reaches its maximum height (apex) and starts descending. After the apex, the vertical component of the velocity becomes negative as the projectile moves downward.

The horizontal component of the velocity remains constant throughout the motion, assuming there is no air resistance. Therefore, the velocity (magnitude of the velocity vector) is at its maximum at the beginning of the motion when the projectile is launched.