Speed of Sound Question?

Question

Ok, lets say you were in a jet airplane going 5 miles per hour under the speed of sound. Say then that you threw a ball to your friend down the aisle at 10 miles per hour.

Would that ball then break the sound barrier and create a mini sonic boom?

From another perspective, if you threw the ball out the window instead of down the aisle, would the effect be different (assuming wind resistence did not slow the ball)?

Ok, I am getting a lot of answer referring to the speed of the air inside the plane.

Lets say a jet is travelling 190 miles an hour below the speed of sound, but has a 200 mph tail wind. Does it break the sound barrier?

Answer 1

for the first part of the question, no the ball would definitely not be going faster than the speed of sound since you are in a closed area and the air inside the plane is static. the ball is traveling at 10mph in the aisle towards your friend (and slowing until the ball is caught)

For the second part of the question (again assuming you CAN open the window and that wind resistance would not slow the ball) yes the ball would in fact surpass the speed of sound. But that would be virtually impossible since if you did have the window open, you would be subjected to a 770mph wind (at sea level, 70 °F) at that point throwing a ball would be impossible. but lets say you could survive a 770mph wind and you were strong enough to still throw a ball, then yes it would surpass the speed of sound.

Answer 2

The ball would not break the sound barrier because it would travel at 10 mph relative to the air in the plane.

The answer to your second question is yes. Relative to the wind outside the ball would travel faster.

Other than amount of energy, a sonic boom isn't much different than the sound you make when you speak or clap your hands or snap your fingers. All sound including sonic booms comes from compressing air and the resulting wave created as it disperses.

When an object moves faster than the speed of sound (which is basically the speed of the molecules bouncing off each other), the air molecules in front of the object don't have time to move out of the way and so they compress and is under higher pressure. This higher pressure air then disperses itself as a wave and creates a sound (or a sonic boom).

Answer 3

The ball inside the airplane would not break the speed of sound, as it is only traveling 10 mph in relation to the air around it.

However, I do suspect that if you did manage to stick your arm out the window and actually throw a ball faster than the plane is traveling, assuming that the wind resistance would not rip your arm right out of the socket, you would creat a mini sonic boom. But, in reality, you are having to overcome wind resistance and actually throw the ball over 700 mph. It would not be any easier than if you were standing on a baseball field, attempting to throw a ball fast enough to break the speed of sound.

Answer 4

No, the airspeed has to be the speed of sound.

If you attatched a bb gun to the top of the plane **very securely!**

Maybe by welding or something, and then remote controlley shot it, then it would break the sound barrier and go Pop.

Very briefly probably, since the ball will lose speed very quickly, and might even hit the gun on the way back.


If your 747 is in a helping jet stream then it might be pushing you past the speed of sound relative to the ground, but you are still not a supersonic body, because it's the air around you that counts.

Answer 5

It would not create a sonic boom. The ball is moving at 10 mph through the air in the plane. If you could throw it out the window, it would teh create a sonic bom.

Answer 6

Assuming no wind resistance, there is no sonic boom. You can't have it both ways.

Answer 7

First question No.
Next; it would follow the plane along.