Ball bouncing on the floor - Normal reaction?

In summary, the normal force is greater than the weight when a ball bounces on the floor due to conservation of energy, not Newton's third law. The two pairs of equal and opposite forces are the Earth's gravitational force on the ball and the ball's gravitational force on the Earth, and the contact force of the floor pushing up on the ball and the ball pushing down on the floor. The acceleration of the ball is determined by the net force on it, which is upwards during its interaction with the floor.
  • #1
sanado
56
0
Hey guys,
Was just wondering if you could help me with what seems like a simple physics question.

When a ball bounces on the floor, is the normal force greater than that of the weight, resulting in the bloor bouncing upwards?

Or

Is it the case where the normal reaction force is the same as the weight and the only reason why the ball bounces back up is because the balls kinetic energy is transformed into strain energy which inturn is converted back into kinetic energy?

Or

Neither of the two
 
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  • #2
sanado said:
Hey guys,
Was just wondering if you could help me with what seems like a simple physics question.

When a ball bounces on the floor, is the normal force greater than that of the weight, resulting in the bloor bouncing upwards?

Or

Is it the case where the normal reaction force is the same as the weight and the only reason why the ball bounces back up is because the balls kinetic energy is transformed into strain energy which inturn is converted back into kinetic energy?

Or

Neither of the two
All of the first and sort of part of the second. The normal force is greater than the weight (it has to be fore a net acceleration) because of conservation of energy.
 
  • #3
"All of the first and sort of part of the second. The normal force is greater than the weight (it has to be fore a net acceleration) because of conservation of energy"

Well ifs that's the case, why is the normal force greater. Doesn't Newtons third law state that for every action there is an equal but opposite reaction? So wouldn't this mean that the acceleration would be equal to the normal force?
 
  • #4
I think another reason is that action and reaction act on two different bodies. Ball exerts a force on the ground while ground in reaction,exerts a force on ball so it bounces up. They do not cancel each other's effect however they are equal in magnitude
 
  • #5
sanado said:
Well ifs that's the case, why is the normal force greater. Doesn't Newtons third law state that for every action there is an equal but opposite reaction?
The normal force and the weight are not 3rd-law pairs. The pairs of forces that are equal and opposite per Newton's 3rd law are:
1) The Earth's force of gravity pulling the ball down (a.k.a., the weight) and the ball's force of gravity pulling the Earth up.
2) The contact force of the floor pushing up on the ball (the normal force on the ball) and the contact force of the ball pushing down on the floor.
So wouldn't this mean that the acceleration would be equal to the normal force?
The acceleration of the ball is determined by the net force on it via Newton's 2nd law. During its interaction with the floor, the net force is upwards (Net force = Normal - weight), so the acceleration is upwards.
 

1. What is the normal reaction force when a ball bounces on the floor?

The normal reaction force is the force exerted by a surface in response to an object resting on it. In the case of a ball bouncing on the floor, the normal reaction force is equal to the weight of the ball, which is the force of gravity pulling it towards the ground.

2. Why does a ball bounce higher on a hard surface compared to a soft surface?

When a ball bounces, it compresses and deforms the surface it hits before springing back to its original shape. A hard surface, like a concrete floor, is less deformable, so more of the ball's energy is transferred back to it, causing it to bounce higher. A soft surface, like a carpet, absorbs more of the ball's energy, resulting in a lower bounce.

3. Does the size or weight of the ball affect the normal reaction when it bounces?

Yes, the size and weight of the ball do affect the normal reaction when it bounces. A heavier ball will have a greater normal reaction force because it has a greater weight, and a larger ball will have a larger surface area to compress, resulting in a larger normal reaction force.

4. How does air pressure affect the normal reaction force of a bouncing ball?

The air pressure inside a ball can affect its bounce. A ball with higher air pressure will be more rigid, resulting in a higher normal reaction force when it bounces because it will compress less when it hits the ground. On the other hand, a ball with lower air pressure will be less rigid, resulting in a lower normal reaction force when it bounces because it will compress more when it hits the ground.

5. Can the angle at which a ball bounces affect the normal reaction force?

Yes, the angle at which a ball bounces can affect the normal reaction force. When a ball bounces at a steeper angle, the normal reaction force will be greater because the ball has a higher velocity when it hits the ground. When a ball bounces at a shallower angle, the normal reaction force will be lower because the ball has a lower velocity when it hits the ground.

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