Quote:
Originally Posted by raaaid
friction in a fluid is:
force of friction=k*h*v where k is a constant that depends on the fluid , h depends on the shape of the object and v is the velocity the object has
so you can see if the object is acelerating v will grow eventually getting to be equal both the force that causes the aceleration and the force of friction reaching the terminal velocity that a parachutist fro example reaches
but on a surface its different:
force of friction=normal force*MU, where mu is a constant
but the problm here is that this means that if you apply to an object a force bigger than this force of friction it will be acelerating for ever(force applied-force of friction)= m*a (f=ma which btw is also proved wrong by relativity)
so in this case terminal velocity is NOT reached
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First example, you reach terminal velocity, the downwards force is constant. You are correct.
The second example is theoretical. If we could have infinite power then you would not reach terminal velocity- you are in powered movement, not freefall. There is no terminal velocity in powered movement, rather a final velocity based on the thrust generated and the air and frictional resistances.
Each engine in the car will have a limit to the force it generates which governs top speed. Top speed has nothing to do with terminal velocity, unless you are driving off a rather tall cliff!