Normal force on a car rounding a banked curve

In summary: Physics. In summary, the normal force on a car rounding a banked curve is mg/cos θ, where θ is the banking angle of the road. This is because the net force on the car in this situation is horizontal towards the center of the circle, resulting in a component of the normal force in the direction of the net force. This is different from the situation on an inclined plane where the net force is downward and there is no component of the normal force in the direction of the net force. The diagram on pg. 114 of the textbook shows a single cross-section of an inclined plane, and if the car is going slow enough, the normal force would approach mg cos
  • #1
junaid314159
48
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This is my first thread on the forum. I'm really glad to have found this wonderful resource. I have a lot of intuition in mathematics and one of my dreams has been to have the same level of intuition in physics. With your help I hope I can achieve that.

I was reading an example in Physics (P&A) - Giancoli - 6th Edition and wanted to try to get a deeper understanding of something. Specifically, I am looking at pg. 114 - Example 5-7 if anyone has the textbook handy. I will explain the question here so that you can understand it on its own.

When a car is rounding a banked curve, the normal force on the car from the road is:
Fn = mg/cos θ, where θ is the banking angle of the road and the center of the car is going in a circle through a horizontal plane.

I wanted to get a deeper understanding as to why the normal force was not what it usually is on an inclined plane, namely Fn = mg cos θ.

I understand that the net force on a car resting on an inclined plane is downward and angled therefore the normal force has no component in the direction of the net force, while in the case of a car going around a banked curve, the net force is horizontal towards the center of the circle in which case the normal force does have a component in the direction of the net force. I'm just trying to better understand what the unique differences are between this situation and the inclined plane which lead the normal force being mg/cos θ.

When you look at the diagram on pg. 114, it is a single cross-section of an inclined plane so one would imagine that if the speed of the car was slow enough, near enough to zero, all you would have is a car on an inclined plane and then the normal force should be close to mg cos θ as it would be exactly that if the speed of the car were zero. Does the normal force then abruptly go from mg/cos θ to mg cos θ when the car stops?

Your insight is really appreciated.


Junaid
 
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  • #2
There are essentially only 2 forces acting on the car
1) the weight mg acting vertically down
2) the normal reaction, Fn from the track
( this is assuming that friction can be ignored )
The normal reaction has 2 components...the vertical component FnCosθ must equal the weight mg
So FnCosθ = mg
The horizontal component is directed towards the centre of the circle and is equal to the centripetal force.
 
  • #3
Thanks
 

Related to Normal force on a car rounding a banked curve

1. What is normal force on a car rounding a banked curve?

The normal force on a car rounding a banked curve is the force exerted by the road on the tires of the car perpendicular to the surface of the road. It is also known as the support force and is necessary to keep the car from sliding off the road.

2. How is normal force affected by the bank angle of a curve?

The normal force is affected by the bank angle of a curve because it is responsible for providing the necessary centripetal force for the car to travel along the curved path. A higher bank angle results in a higher normal force, while a lower bank angle results in a lower normal force.

3. Does the speed of the car affect the normal force on a banked curve?

Yes, the speed of the car does affect the normal force on a banked curve. As the speed of the car increases, the centripetal force required to keep the car on the curved path also increases, resulting in a higher normal force.

4. What happens if the normal force is too high on a banked curve?

If the normal force is too high on a banked curve, it can cause the car to experience more friction and potentially lose traction, leading to a potential loss of control. It is important for the normal force to be balanced with the other forces acting on the car to maintain stability.

5. How can the normal force be calculated on a banked curve?

The normal force on a banked curve can be calculated using the equation F_N = (m*v^2)/r, where F_N is the normal force, m is the mass of the car, v is the speed of the car, and r is the radius of the curve. This equation takes into account the centripetal force needed for the car to travel along the curved path.

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