Throwing a ball in an airplane

  • #1
doglover9754
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Main Question or Discussion Point

If you have seen my past thread about where a ball would end up in a car moving forward then this is kind of an extension of it.

What I was wondering in that thread is where would a ball end up, being thrown straight up in a car driving forward (no windows/AC)? I thought it would land in back of me.

I have just been to Japan and I tried this inside a plane. I figured that a plane is moving faster so why not try it since it’s probably going to have a more noticeable effect (since it’s faster it would maybe land WAY in back of me). So, I tried. I threw a stress ball up in the plane and I caught it in the same place that I threw it. Why? According to one of Newton’s Laws Of Motion, an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force. Shouldn’t it have kept on going up while we keep going forward in the plane resulting in the ball landing behind me? I also tested it with my phone, a heavier object, to make sure that it wasn’t the weight of the object being thrown upwards. The same thing happened. I don’t get it. Can someone explain to me why it isn’t behind me? Is it the height I’m throwing it at? Or some other factor? I’m not sure. Any responses would be greatly appreciated!
 
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  • #2
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Dear doglover9754, I hope you consider becoming a particle physicist when you grow up. You have the right kind of curiosity. Never stop asking questions.

I am not familiar with hydraulic computers, and I am not qualified to explain the functionality of the flaps on the airplane wings, but I will try to address your second question.
Here is the scenario:
You and the ball are on the airplane. The airplane is travelling horizontally, at a constant speed.
So now, you and the ball and the plane are all moving at the same speed, in the same direction.

Let us look at the forces on the ball horizontally and vertically. Separately.
Horizontally: No forces acting either way, so the ball keeps moving at the same speed (towards/from japan).
Vertically: You apply a force upwards (throwing the ball), the ball moves upwards. During its flight, the only forces acting on the ball are gravity and air resistance.
Let us skip the air resistance, since it is so small. Gravity is = mass times 9.81m/s2. It acts on the ball in mid-flight, and when you catch it again. But when the ball is in mid-air, the gravity is accelerating it downwards, towards your hand, because it is the greatest force.
I hope you see now that Newton still wins. (Newton always wins by the way).

Things that could change your experiment:
1) If you where super-strong, and threw the ball so far up, that its current "horizontal" speed would be enough to keep it in an orbit around the earth, like a satelite. In this case the ball would keep moving and never return.

2) If you conducted the same experiment during the acceleration or deceleration of the plane (the windows of time in which the speed is changed, like when you are on the runway and the plane is boosting forwards). When the plane is boosting on the runway, you can feel a force acting not only on the ball, but also on you. This force, by definition, accelerates (changes the speed) of a mass (such as yourself). If the ball is in the air during this time, then it will not be affeted by the force, and it will lag behind you and the plane. (You might not notice though).
 
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  • #3
256bits
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According to one of Newton’s Laws Of Motion, an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force
There's your answer right there!
The ball in your hand is travelling the same speed( velocity) as you and the airplane - in motion relative to someone on the ground.
If you throw the ball straight up, what force would cause the ball to change its speed?
Or,,
You, the seats, your drink, the passengers, the air in the plane, and the ball are at rest relative to the plane.
Throwing the ball up, what force are you thinking would cause the ball to be set in motion relative to the plane.
 
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  • #4
ZapperZ
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If you have seen my past thread about where a ball would end up in a car moving forward then this is kind of an extension of it.

What I was wondering in that thread is where would a ball end up, being thrown straight up in a car driving forward (no windows/AC)? I thought it would land in back of me.

I have just been to Japan and I tried this inside a plane. I figured that a plane is moving faster so why not try it since it’s probably going to have a more noticeable effect (since it’s faster it would maybe land WAY in back of me). So, I tried. I threw a stress ball up in the plane and I caught it in the same place that I threw it. Why? According to one of Newton’s Laws Of Motion, an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force. Shouldn’t it have kept on going up while we keep going forward in the plane resulting in the ball landing behind me? I also tested it with my phone, a heavier object, to make sure that it wasn’t the weight of the object being thrown upwards. The same thing happened. I don’t get it. Can someone explain to me why it isn’t behind me? Is it the height I’m throwing it at? Or some other factor? I’m not sure. Any responses would be greatly appreciated!
When you are on the ground, when you toss the ball vertically upwards (the same way you did on the plane), does the ball land somewhere else?

You must be wondering why I'm asking such a stupid question. But think about it. According to some alien on another planet, the earth is moving VERY fast in one direction. In other words, you ARE in the same situation as you were on the plane!

Zz.
 
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  • #5
doglover9754
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Dear doglover9754, I hope you consider becoming a particle physicist when you grow up. You have the right kind of curiosity. Never stop asking questions.
I’m glad you think that. With that recommendation, I have a second career option in mind. Thanks! For now my eyes are set on being a mechatronics engineer.
 
  • #6
doglover9754
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There's your answer right there!
The ball in your hand is travelling the same speed( velocity) as you and the airplane - in motion relative to someone on the ground.
If you throw the ball straight up, what force would cause the ball to change its speed?
Or,,
You, the seats, your drink, the passengers, the air in the plane, and the ball are at rest relative to the plane.
Throwing the ball up, what force are you thinking would cause the ball to be set in motion relative to the plane.
Hmmmm... I think I get it. So if I hold the ball, it’s going to go at the same speed as me, the airplane, and anything connected to it. If I let it go, it should keep going at the same speed because I really didn’t do anything to affect its speed? I’m not sure.
 
  • #7
doglover9754
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When you are on the ground, when you toss the ball vertically upwards (the same way you did on the plane), does the ball land somewhere else?

You must be wondering why I'm asking such a stupid question. But think about it. According to some alien on another planet, the earth is moving VERY fast in one direction. In other words, you ARE in the same situation as you were on the plane!

Zz.
That makes so much sense! I throw a ball at home and it lands where I threw it unless I threw it in a different direction. I’ve never thought of that. Thanks!
 
  • #8
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Hmmmm... I think I get it. So if I hold the ball, it’s going to go at the same speed as me, the airplane, and anything connected to it. If I let it go, it should keep going at the same speed because I really didn’t do anything to affect its speed? I’m not sure.
Yes, you've pretty much got it. You probably haven't encountered vectors yet, but when you do you'll find that they give you a useful mathematical language for describing what's going on.
 
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  • #9
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Hmmmm... I think I get it. So if I hold the ball, it’s going to go at the same speed as me, the airplane, and anything connected to it. If I let it go, it should keep going at the same speed because I really didn’t do anything to affect its speed? I’m not sure.
That idea is called a frame of reference, which is useful.
 
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  • #10
doglover9754
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That idea is called a frame of reference, which is useful.
Cool! Sounds like that will come in handy someday
 
  • #11
doglover9754
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Yes, you've pretty much got it. You probably haven't encountered vectors yet, but when you do you'll find that they give you a useful mathematical language for describing what's going on.
My math teacher has mentioned that once in math. She said she doesn’t teach it so we’ll have to wait to learn it.
 

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