It is reasonable to assume that covering for example an airplane with Teflon would lead to it having lower wind resistance? The reason why I ask is that Teflon "has one of the lowest coefficients of friction against any solid." according to Wikipedia.
[Physics] Does Polytetrafluoroethylene (Teflon) have low wind resistance
frictionmaterial-science
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According to Newton, Inertia is the resistance of a body due to which it resists any change in its state of motion. Whether it is in the state of rest or in motion inertia will always be present. That means even is state of motion body will resist any change in its motion. Hence when the ball is in the air, it will resist change in it's motion as well (which is straight line).
Friction is itself a force. And you said that, "it is against the direction of force". That means the friction is a force which will act against the net force acting on the particles, which is incorrect. Friction is not inertia and it will not help inertia.
Friction is a force acting between to bodies against their "relative" motion (to understand the term "relative", see how friction can sometimes increase the velocity of a body in a given frame.) And then you said, "which is against inertia so would friction be helpful too in supporting inertia of a body consequently." I am not what you want to say here but I think this is not a correct statement. Inertia is a property not a force. And $F = \frac{\mathrm{d}(mv)}{\mathrm{d}t}$, rate of change of momentum with time. Now you can see that if force is same and we have a heavier mass and a lighter constant mass, change in velocity ($a = \frac{F}m$) will be less in case of heavier mass. So we can say that heavier mass has more inertia than the lighter mass.
You may want to look into the definition of inertia again. I hope I was helpful. : )
As BowlOfRed points out the incoming air has a certain temperature and the convective flow will tend to bring the temperature of the object towards the temperature of the incoming air.
In the case where the incoming air was going very fast it gets heated through adiabatic compression before it reaches the object, so the incoming air is at higher temperature than the free stream temperature, but it will still cool the object if it is at an even higher temperature.
Similarly, if you take something out of the freezer, a gentle breeze will actually have a warming effect on the object bringing it closer to the temperature of the incoming air.
If you want to know the relationship between the equilibrium temperature and the free stream temperature vs. velocity that's given by the isentropic flow equation:
$$T=T_0\,\left(1+\frac{\gamma-1}2 M^2 \right)$$
Where $T$ is the surface temperature (in Kelvin or Rankine), $T_0$ is the free stream temperature (in Kelvin or Rankine), $\gamma$ is the ratio of specific heats (1.4 for air), and $M$ is the Mach number.
Best Answer
The resistance to flow through air is not the same as the coefficient of friction.
When air is flowing over a surface the flow is generally laminar very near to the surface, though it may be turbulent further away from the surface. Anyhow, in laminar flow the air immediately next to the surface isn't moving. The air doesn't flow by sliding over the surface, it flows by shearing the layers of air near the surface. There is no "frictional sliding" analagous to two solids sliding over one another, so there is no concept of a friction co-efficient.
Now to Teflon. You need to be very careful when talking about Teflon having a low friction. It has a low surface energy, so other materials tend not to adhere to it, and it's the adhesion between surfaces that is the physical origin of friction. This adhesion may be Van der Waals forces, dipolar forces or even chemical bonding, and Teflon is non-polar and chemically inert hence the low adhesion.
But outside the laboratory friction has various components. In particular you get energy losses due to plastic deformation in the surfaces that are sliding over each other, and this manifests as a frictional force i.e. the energy loss means you need to do work to slide the surfaces. Teflon dissipates more enery in this way than e.g. glass, so the friction is not necessarily lower than e.g. glass with a good boundary lubricant.