Newton's Third Law Tire on Road Question

[ChristPuncher]

Homework Statement

I was reading a textbook that gave an example of Newton's Third Law using the explanation for every force there is an equal and opposite force. The example given was a car tire on the road being accelerated moving in the negative x direction. In the supplemental diagram (see image) there is a vector force horizontally from the tire as a result of the car being accelerated and the force of the road opposite the direction of motion. The book then goes on to state that the car actually moves the road but because of the mass of the Earth its unnoticeable.

My question isn't so much about the equal and opposite as it is where does the car touch the road so that it moves when being accelerated (i.e How can the car exert a force downward on the road when the car is being accelerated horizontally?).

Does the tire have a tangential line of force in the negative x direction parallel to the road right where it touches the road?

 

[PhanthomJay]

, Think about what would happen if you were to accelerate from rest with your car tires on a very smooth icy surface. Or with your car on a lift with the tires suspended in air with no contact surface beneath, and your foot pressing on the acceleartor pedal. Would the car move forward? What horizontal force must be acting in order for it to accelerate forward?

 

[kerimek]

I can provide an explanation for this question using Newton's Third Law. When a car is being accelerated, the force is being applied by the engine, which creates a forward motion for the car. This force is then exerted onto the tires, which in turn exert an equal and opposite force onto the road. This force is distributed over the area of the tire that is in contact with the road, resulting in the car moving forward.

To answer your question about where the car touches the road, it is important to understand that the tire is not a single point, but rather a surface that is in contact with the road. This surface is in constant motion due to the rotation of the tire, and the point of contact with the road is constantly changing. Therefore, the force is being applied over a larger area rather than a single point.

Furthermore, the tangential line of force that you mentioned is correct. The force applied by the tire on the road is in the same direction as the motion of the car, and it is distributed over the contact area between the tire and the road. This allows the car to exert a downward force on the road, resulting in the car moving forward.

In summary, the car exerts a force on the road through the tires, which is distributed over the contact area between the tire and the road. This force, in turn, allows the car to move forward. This is an excellent example of Newton's Third Law in action, where every action has an equal and opposite reaction.