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jk_16
in air resistance (drag) is acceleration constant??
Yes, it is a force. But its magnitude, direction, behavior, etc is a function of several other variables related to the nature of the object experiencing the resistance (e.g. its shape, velocity, its environment, the properties of the air, etc).
What do you mean? Acceleration has no influence on drag force, so \(\frac{dF_{drag}}{da}=0\) , but it has an influence on the acceleration since it's a force.
***Instantaneous acc has no influence on drag
Assuming ceteris paribus, as an object travels at a constant velocity in a straight line through non-turbulent air, it experiences a constant acceleration backwards caused by the air.
the grap of a v-t system under the influence of air resistance..is not a constant v(t)
That is, in order to maintain constant velocity, the object must constantly be accelerating forward with a force equal but opposite to the force caused by the air resistance. It's like driving your car at high speeds; you have to constantly give it some gas to maintain your velocity, which is goes against Newton's law that an object in motion remains in motion. The resistance caused by air (and internal friction) accounts for this need to constantly accelerate the car.
If an object is ONLY encountering drag, \[F = \frac{1}{2}cAv^2\]\[m a = \frac{1}{2}cAv^2\]\[k=.5cA/m; \frac{d v}{dt}=kv^2\]
@vf321 where did you get the initial F=1/2 cAv^2 from
That's the formula for drag, if I remember correctly.
F=12cAv2 ma=12cAv2 k=.5cA/m;dvdt=kv2