A projectile is launched straight 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, it will reach a maximum height and then fall back down to its starting point. During this motion, the only force acting on the projectile is the force of gravity, and air resistance is negligible.

At the maximum height, the projectile's velocity will be zero, and then it will start falling back down towards the ground. As the projectile falls back down, the gravitational force will accelerate it, and it will gain speed.

However, since the projectile is returning to its starting point, it will have the same speed as it did when it was launched upward. This is because the time it takes to go up and come back down is the same, and the acceleration due to gravity is constant.

Therefore, the speed of the projectile upon returning to its starting point is 50 m/s, which is the same as the initial velocity. Thus, the correct answer is B) 50 m/s.

A Projectile Is Launched Straight Upward at 50 M/s