Friction Questions: How Does a Car Turn?

In summary, the concept of friction can be confusing when considering the motion of objects in different directions. The direction of the friction force is always opposite to the direction of motion and is dependent on the applied forces. In the case of two blocks moving at the same speed, there may still be static friction between them depending on their relative motion.
  • #1
gracy
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https://www.physicsforums.com/threads/friction-questions-how-does-a-car-turn.150321/
I have a doubt regarding the following line of post 6 of the above particular thread According to below lines of the mentioned post
The applied force will accelerate the box towards the north, so it will move in a curve. The friction force is always along the tangent to that curve and opposite to the direction the box is moving. So the component of friction force in the south direction will increase and the component in the west direction will decrease.
the diagram would be
upload_2015-3-25_0-16-27.png


But the below lines of the very same post
If your box is moving east, the dynamic friction force is towards the west. If you suddenly apply a force towards the north at time t=0, the dynamic friction force at t=0 will still be towards the west.
Are contradictory of my diagram this is my opinion ,I think I am wrong I am missing something.Please guide me.
 

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  • #2
gracy said:
the diagram would be
upload_2015-3-25_0-16-27-png.80917.png
Not sure what you are drawing here. To find the direction of the dynamic friction, you must draw the path of the box. It starts out moving east, then begins to curve towards the north as the northern force is applied. Your diagram seems to show the path instantly changing when the force is applied.
 
  • #3
If I say I have drawn the diagram of that instant when the applied force in north direction has become large enough,will my diagram be correct?
 
  • #4
One more query friction is
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
So ,let's take the two blocks which are in contact are moving with same velocity.That means there is not an relative motion between them so no friction?
 
  • #5
gracy said:
If I say I have drawn the diagram of that instant when the applied force in north direction has become large enough,will my diagram be correct?
It doesn't seem right to me, but I'm not sure what you are trying to illustrate.
 
  • #6
gracy said:
So ,let's take the two blocks which are in contact are moving with same velocity.That means there is not an relative motion between them so no friction?
If there's no relative motion between the blocks, then there is no dynamic (kinetic) friction between them. There may well be static friction between them.
 
  • #7
One typo is here .I meant .That means there is not any relative motion between them ,so no friction?
 
  • #8
gracy said:
So ,let's take the two blocks which are in contact are moving with same velocity
Doc Al said:
There may well be static friction between them.
As they are moving,will there be static friction?
 
  • #9
gracy said:
One typo is here .I meant .That means there is not any relative motion between them ,so no friction?
If there is no relative motion, there is no dynamic friction.
 
  • #10
gracy said:
As they are moving,will there be static friction?
Just because they are moving with respect to some frame does not mean there cannot be static friction between the surfaces. Depends on the situation.

For example: Say one block is sitting on top of the other. And the bottom block is being pulled along (accelerating) while the top block comes along for the ride. In this case, both blocks are moving at the same speed, yet there is static friction between them.
 
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1. What is friction and how does it affect a car's turning?

Friction is a force that opposes motion between two surfaces in contact. In the case of a car turning, friction plays a crucial role in providing the necessary grip between the tires and the road surface. Without sufficient friction, the car would not be able to turn effectively and could potentially skid or slide.

2. How does the weight of a car affect its turning ability?

The weight of a car affects its turning ability by influencing the amount of friction between the tires and the road surface. A heavier car will have more weight pressing down on the tires, increasing the friction and providing better grip, thus allowing for tighter turns. On the other hand, a lighter car may have less grip and may not be able to take turns as sharply.

3. Can the type of tires on a car impact its turning?

Yes, the type of tires on a car can greatly impact its turning ability. Tires with a larger surface area and deeper treads provide more friction and thus, better grip on the road. This allows for more precise and controlled turns. Additionally, different types of tires, such as winter tires or performance tires, are designed specifically for certain road conditions and can greatly affect a car's turning ability.

4. How does speed affect a car's turning ability?

The speed of a car can greatly impact its turning ability due to the amount of friction between the tires and the road surface. When a car is traveling at high speeds, there is less time for the tires to grip the road and generate enough friction for a smooth turn. This can result in the car sliding or skidding, making turns more difficult to navigate. On the other hand, turning at lower speeds allows for more time for the tires to grip the road, making it easier to turn.

5. Are there any other factors besides friction that affect a car's turning?

Yes, there are other factors that can affect a car's turning, such as the design and suspension of the car, the road conditions, and the driver's skill level. A well-designed car with good suspension can help maintain traction and improve turning ability. The road conditions, such as wet or icy roads, can also greatly impact a car's ability to turn. And of course, a skilled driver who understands how to use friction to their advantage can greatly improve a car's turning ability.

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