A projectile is launched vertically upward at 50 m/s. If air resistance is negligible, its speed upon returning to its starting point is
A)less than 50 m/s.
B)50 m/s.
C)more than 50 m/s.

Question

Quizplus · Accepted Answer

When a projectile is launched vertically upward, its initial velocity is only acting against gravitational acceleration (g). Therefore, the projectile slows down until it reaches its maximum height (where its velocity becomes zero). After that, the projectile starts to fall back to its starting point under the influence of gravity. However, the gravitational acceleration remains the same and in the same direction. Therefore, the velocity of the projectile increases as it falls back to the starting point.

Since air resistance is negligible in this scenario, there is no external force acting on the projectile during its trajectory. Therefore, the projectile should return to its original height with the same speed (magnitude) as it had when it was launched. Thus, the speed upon returning to its starting point is the same as the initial velocity, which is 50 m/s.

A Projectile Is Launched Vertically Upward at 50 M/s