Wouldn’t an equal and opposite be exerted on your hand, thus canceling out the force and having no net change on the ball?
Noticeably different from a rocket, where propelled material is the force that drives the rocket forward.
I used to remember the answer to this question, but my physics is kinda fuzzy.
In: Physics
You’d go backwards an equal amount of momentum that the ball would go forward. Since you are, presumably, more massive than the ball, the ball would go faster than you would.
If you push a ball in space, the ball pushes back and you/the ball fly apart. The ball pushing you is why you fly away. You pushing the ball is why the ball flies away.
No, the forces don’t cancel out. You can push away the ball, but the ball also pushes you away–so the ball and you accelerate in opposite directions. The force is the same, but acceleration also depends on mass, so you can push a little ball a lot faster than it can push a big person.
This is just like with a rocket. Either the ball or you (depending on how you prefer to think about it) is like the exhaust being expelled in the opposite direction the rocket is going.
You don’t have to be in space for your logic. The 3rd Law applies on Earth too.
Anyway, you have to remember the forces are acting on DIFFERENT objects. You push on the ball, and the ball pushes on you with an equal and opposite force. If the force on the ball is greater than any other friction forces, then there will be a net force on the ball and it will accelerate. Same for the force on you. However, you are more massive than the ball, so the equal forces accelerate the ball and you a different amount.
The force generated acts equally on both objects. Think of when you push on a wall. You can feel yourself moving backwards. Not quite the best example, as it can better be explained by inertia.
People often misinterpret Newton’s third law to mean forces that cancel out like: <—hand—>
But in reality it looks more like
<—Hand
Ball—>
The forces are still equal and still opposite of each other but they are acting on different objects which is why there is no cancelling out.
As for what happens, you both move away from each other with the light object moving away faster than the heavier object.
If, as you say in you example, you push a ball in zero gravity, the ball will exert an equal and opposite force on you. The difference is inertia. Let’s say that the ball is considerably smaller than a human, a baseball for instance.
If you grab the ball and throw it like you would normally throw it, one handed in an arc over your shoulder, two things would happen. The ball would go forward as you intended, but you would also rotate backward around your center of gravity, as if you performed a backflip. The effect experienced by you would be less severe because of the difference in mass (and therefore inertia) between yourself and the smaller ball.
You can think of Newton’s Third Law as meaning something like “forces come in pairs”. There are a couple of easy rules to identify the forces in action/reaction pairs:
First, the forces in a pair always act on *different objects*. If one force is acting on the ball, then the reaction force cannot be another force acting on the ball.
Second, the forces in a pair are always *the same type of force*. If the force in question is a contact force (like a hand pushing on a ball), then the reaction force *also* must be a contact force. If the force is gravitational, then the reaction force must also be gravitational, etc.
are you letting go of the ball? if you hold on itll push your body back as you move the ball away and closer as you pull back or stop. if you let go and the ball gains momentum you gain the same momentum in the oposite drection
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