Zero Friction on the Moon: Driving at Constant Velocity Without Air Resistance

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Discussion Overview

The discussion revolves around the concept of friction when driving a vehicle on the Moon, specifically under conditions of zero air resistance and on a surface with zero friction, such as ice. Participants explore the implications of these conditions on the vehicle's motion and the nature of forces acting on it.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that if a vehicle is driving at constant velocity on a surface with zero friction, there is negligible friction acting on the tires.
  • Others argue that even with negligible friction, there is still some rolling resistance due to the deformation of the tire and the road surface.
  • A participant questions whether the friction force, if present, acts in the same direction as the car's motion or in the opposite direction.
  • It is suggested that in the absence of friction, the tire may rotationally decelerate while the car maintains its speed due to other factors like tire flexion.
  • Another participant emphasizes that a coasting car will eventually stop due to friction, which includes both rolling resistance and air resistance, even if air resistance is not a factor in this scenario.

Areas of Agreement / Disagreement

Participants express differing views on the presence and role of friction in this scenario, with no consensus reached on whether friction exists or how it affects the vehicle's motion.

Contextual Notes

Participants discuss the definitions and implications of friction, rolling resistance, and the conditions under which these forces operate, highlighting the complexity of the topic without resolving the underlying assumptions.

Who May Find This Useful

This discussion may be of interest to those studying physics, particularly in the areas of mechanics and forces, as well as individuals curious about the effects of different surface conditions on vehicle dynamics.

Mohamad
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Suppose we are driving on moon (I mean there is not air resistance) at a constant velocity. Suddenly the car goes on an icy land (the friction is zero). What happens?
In other words, if we drive at constant velocity and there isn't air resistance, Is there any friction force between tires and road? If yes, why?
 
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Mohamad said:
Summary: Is there any friction force when we drive at a constant velocity?

Suppose we are driving on moon (I mean there is not air resistance) at a constant velocity. Suddenly the car goes on an icy land (the friction is zero). What happens?
In other words, if we drive at constant velocity and there isn't air resistance, Is there any friction force between tires and road? If yes, why?
If a wheeled vehicle is neither braking nor accelerating, then there is negligible friction. Technically there is a "rolling resistance", which may be also small, and explains why rolling is so efficient. An object, wheel or ball, rolling on a smooth surfaces slows down gradually. Whereas, a flat object sliding on a surface tends to slow down under friction.
 
Mohamad said:
...(the friction is zero)...Is there any friction ...
The answer is in your premise.
 
A.T. said:
The answer is in your premise.
No, I only asked my question in two ways. Is there any friction force? and if no, so the car continues its straight route with no problem on an icy land.
 
Mohamad said:
In other words, if we drive at constant velocity and there isn't air resistance, Is there any friction force between tires and road? If yes, why?

Yes. At the place where the tire makes contact with road there is deformation of both the tire and the road.
 
PeroK said:
An object, wheel or ball, rolling on a smooth surfaces slows down gradually.
Are there any differences between a ball and the tire of a car, whereas the tires of car get their force from the engine?
 
Mister T said:
Yes. At the place where the tire makes contact with road there is deformation of both the tire and the road.
Has the friction force the same direction as the car moving or is in the opposite?
 
In the absence of friction (but still with real dissipative tire flexion) the tire will rotationally decelerate but the car will maintain speed . The deceleration of the tire would be caused by differential vertical flexion, not "friction"
 
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Mohamad said:
Has the friction force the same direction as the car moving or is in the opposite?
You can work this out for yourself by considering that a car coasting without power will eventually come to a stop. Because it is coasting without power the only force acting on it will be friction (both rolling resistance and air resistance are forms of friction).
1) what are the initial and final speeds?
2) in view of the answer to #1, what is the change in velocity? (Be careful to get the sign right)
3) acceleration is defined to be the change in velocity over time. What direction is the acceleration?
4) what direction will the force point to produce acceleration in that direction?
 

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