- #1
In summary, the conversation is about identifying the forces acting on a ball at different times and determining if there are any additional forces beyond gravity. The discussion also touches on the concept of air resistance and its relevance in this scenario. Ultimately, it is concluded that in a vacuum, only gravity is acting between points A and B, causing the ball to accelerate downwards. The conversation also briefly mentions Newton's laws and their application to the situation.
- #2
NascentOxygen
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What forces do you think are acting on the ball at A?
- #3
Jirya
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Of course, the gravitation force and a force from the 'table'. The force from the table is greater; and that means that the ball jumps up.
But actually, I'm just interested to know which forces are acting between A and B. A friend of my claim that only the gravitation force is acting. Is that true?
But actually, I'm just interested to know which forces are acting between A and B. A friend of my claim that only the gravitation force is acting. Is that true?
- #4
adjacent
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What about the force when moving through air?Jirya said:
- #5
Jirya
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adjacent said:
I don't see how that's relevant here? :)
- #6
adjacent
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Yes.If your question says air resistance is negligible,it's not relevant.Jirya said:
However,in the OP, you said that you want to know the forces acting on the ball.
You did not say that there's a vacuum there.
Still,there's another force.Think of why the ball is slowing down.Energy is transformed from kinetic to another form.We know that it's not potential energy,soo...
- #7
Jirya
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adjacent said:Yes.If your question says air resistance is negligible,it's not relevant.
However,in the OP, you said that you want to know the forces acting on the ball.
You did not say that there's a vacuum there.
Still,there's another force.Think of why the ball is slowing down.Energy is transformed from kinetic to another form.We know that it's not potential energy,soo...
Yeah, it's in vacuum. My mistake. I should have informed that.
... What are you implying? :-D
- #8
adjacent
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Jirya said:
Oh sorry.I forgot that you only want the forces acting between A and B.
If the place is a vacuum,then the force(s) acting between A and B is Gravity alone.You're right.
- #9
Jirya
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adjacent said:
But why is the ball moving up then?
If only gravity works alone you could imagine that the ball should move downwards?
- #10
adjacent
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Jirya said:
Where is it moving up? It's moving down after some time.
It's actually accelerating downwards. ##\vec F=m\vec a##
A force only accelerated an object in some direction.It does not mean that if you have a force downwards,it should move only downwards.
Think of this: If you throw a ball upwards,why does it move up for sometime instead of falling the moment you release it?
- #11
adjacent
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(Think of this: thing)
At the moment you release the ball,the only force .i.e gravity, is acting downwards.It will then accelerate it downwards(Decreasing the upward velocity).When the upward velocity becomes zero,it stops moving up and starts to fall down.
At the moment you release the ball,the only force .i.e gravity, is acting downwards.It will then accelerate it downwards(Decreasing the upward velocity).When the upward velocity becomes zero,it stops moving up and starts to fall down.
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- #12
Govind_Balaji
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Think of Newton's laws
- #13
Rellek
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Are we assuming no air resistance?
- #14
adjacent
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Govind_Balaji said:
How is Newton's laws going to help here?
-His first law is not useful here because there is an external force acting(Gravity)
-His second law will work but we don't need it here because a is 10m/s^2 or 9.81m/s^2(Depending on the amount of accuracy required)
-His third law will not work here because it's not touching anything.
Note that Jirya wants the forces acting between A and B.
Yeah.Read the posts carefully.Rellek said:
Jirya said:
FAQ: Which forces affect the ball in A, B, C and D?
What are the different types of forces that can affect a ball?
In general, there are four main types of forces that can affect a ball: gravitational force, normal force, frictional force, and applied force. These forces can act individually or in combination to influence the motion of the ball.
How does gravitational force affect a ball?
Gravitational force is a force that is exerted by the Earth on all objects with mass. It causes objects to accelerate towards the Earth's center and is responsible for the downward motion of a ball when it is in the air. The strength of gravitational force depends on the mass of the ball and the distance between the ball and the Earth's center.
What is the normal force and how does it affect a ball?
The normal force is a force that is exerted by a surface on an object that is in contact with it. In the case of a ball, the normal force is equal in magnitude but opposite in direction to the force exerted by the ball on the surface. This force helps to keep the ball in contact with the surface and affects its motion in different ways depending on the angle of the surface and the speed of the ball.
How does frictional force affect a ball?
Frictional force is a force that is exerted by a surface on an object in motion. It acts in the opposite direction to the motion of the object and can either slow down or speed up the object depending on the direction of the force. In the case of a ball, frictional force can affect its motion in different ways, such as causing it to roll or slide on a surface.
What is an applied force and how does it affect a ball?
An applied force is a force that is exerted on an object by an external source. In the case of a ball, this can come from a person kicking or throwing it, or from a collision with another object. Applied force can change the direction or speed of the ball, and its effects depend on the magnitude and direction of the force.