Newton's III law (action/reaction) question

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In summary, the conversation discusses the action/reaction of a tennis ball hitting a racket, the equality of the forces involved, and the reason why they do not cancel each other out. The forces are exerted on different objects, thus they do not cancel each other. The concept of inertia is also mentioned.
  • #1
soicuw
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Homework Statement


This question has three parts, and i think i have a and b down.

a) Describe the action/reaction of a tennis ball hitting a racket:

b) Are the magnitudes of the forces equal?

c)Why don't the forces cancel each other out upon contact?

Homework Equations




The Attempt at a Solution


a)I said the ball pushes against the racket, the racket pushes against the ball
b)Yes.
c)HERE IS WHERE I'm CONFUSED: My guess is because of inertia, but I'm not really sure what inertia is exactly, could someone tell me if I'm correct?
 
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  • #2
soicuw said:

Homework Statement


This question has three parts, and i think i have a and b down.

a) Describe the action/reaction of a tennis ball hitting a racket:

b) Are the magnitudes of the forces equal?

c)Why don't the forces cancel each other out upon contact?

Homework Equations




The Attempt at a Solution


a)I said the ball pushes against the racket, the racket pushes against the ball
b)Yes.
c)HERE IS WHERE I'm CONFUSED: My guess is because of inertia, but I'm not really sure what inertia is exactly, could someone tell me if I'm correct?

Each of the forces is exerted on a different object.
 
  • #3
a)the ball pushes the racket & vice versa.
b)yes.
c)since the two force do not act on same object they do not cancel each other.
 
  • #4
Oh yeah that makes sense, thanks physics geniuses!
 
  • #5


Your answer is partially correct. Inertia is the tendency of an object to resist changes in its motion. In this case, the tennis ball has inertia and therefore, it does not stop moving when it hits the racket. This results in the forces not cancelling each other out upon contact. However, there is another factor at play here which is the elasticity of the materials. When the ball hits the racket, the racket compresses slightly and then springs back, transferring some of the energy back to the ball. This causes the ball to bounce off the racket and continue its motion. So, while the forces are equal, the resulting motion of the objects is not cancelled out due to the combination of inertia and elasticity.
 

What is Newton's third law of motion?

Newton's third law states that for every action, there is an equal and opposite reaction. This means that when an object exerts a force on another object, the second object will also exert an equal and opposite force on the first object.

Can you give an example of Newton's third law in everyday life?

One example of Newton's third law is when you push a shopping cart. As you push the cart forward, the cart exerts an equal and opposite force on you, pushing you backward slightly.

How does Newton's third law apply to motion?

Newton's third law explains that forces always occur in pairs. When one object exerts a force on another object, the second object will exert an equal and opposite force on the first object. This means that the forces are balanced and will not cause a change in motion, unless acted upon by an unbalanced force.

Is Newton's third law always true?

Yes, Newton's third law is always true. It is one of the fundamental laws of physics and has been proven through experiments and observations.

How is Newton's third law related to Newton's first and second laws?

Newton's first law states that an object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an unbalanced force. Newton's second law explains how an unbalanced force will cause an object to accelerate. Newton's third law states that forces always occur in pairs and is related to the other two laws because it helps to explain how an object will react to the forces acting upon it.

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