Which ball will hit the ground first?

[Idrees]

What hits the ground first??

Homework Statement

If we simultaneously throw two tennis balls horizontally from the top of a building, one at 10 m/s and the other at 14 m/s. Neglecting the air resistance, which one will hit the ground first?

Homework Equations

i don't think we use equations, but we have to consider the speed of each ball and how they are thrown horizontally??

The Attempt at a Solution

I think the ball with 10 m/s should hit the ground first because it won't reach far and eventually fall vertically from the top of buliding ?? please help out??

 

[Redd]

They both start with a vertical velocity of 0.

Horizontal velocity does not affect vertical velocity.

 

[mg0stisha]

You could also use equations of projectile motion to confirm this.

 

[mugaliens]

Technically, the 10 m/s tennis ball will hit the ground first, but not for the reason you mentioned.

It's because the Earth is round! The ground where the 14 m/s tennis ball impacts is just a few microns lower, so that ball has further to fall!

Otherwise, assuming flat Earth, they'd both hit at the same time.

 

[modulus]

Yes, considering the Earth is flat, they both will hit at the same time.
The one with an initial speed of 10m/s will travel a less distance and the one with an initial velocity of 14m/s will travel more, but they will take the same time.
You can verify this with this equation:
For motion on the y-axis:- h=u_yt - 1/2gt²

since 'u_y' is zero, the equation simplifies to:-

h= -1/2gt²
or, t=sqrt of (2h/g)

Since 'h' and 'g' are same in the case of both the balls, the time taken by each to reach the ground will be equal.