Question

A physics demo launches a ball horizontally while dropping a second ball vertically at exactly the same time. 1) which ball hits the ground first?

Answer 1

Answer:

Both balls will hit the ground at the same time

Explanation:

The factor which leads to ball falling is the gravity acting on the ball;

The motions along the path of both balls are independent and both balls will obey the following illustration

Using the third equation of motion

s = ut + ½at²

Where s = distance covered by both balls.

u = initial velocity of both balls. Since both balls start from rest, u = 0m/s

a = acceleration; and it's equal to acceleration due to gravity.

a = g

By substituton

s = 0 * t + ½gt²

s = 0 + ½gt²

s = ½gt²

Make t the subject of formula

gt² = 2s

t² = 2s/g

t = ±√(2s/g)

But time can't be less than 0 (in other words, negative)

So,

t = √(2s/g)

It'll take both balls √(2s/g) time to hit the floor

Answer 2

-Both hit at the same time ; their initial velocities started at zero