- #1
unscientific
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Homework Statement
Here I have drawn for the following scenarios:
Linear Resistance FR = -k[itex]\vec{v}[/itex]
a)Free-fall starting from rest, downwards as positive.
Now it gets trickier...
b)Free-fall starting from rest, upwards as positive.
My reasoning is as such:
Since the resistive force always points opposite to the velocity vector, in this case the velocity is pointing downwards since the object is moving downwards:
v = -vi. Hence F = -bv = bv i
The force points upwards.
Quadratic Resistance
F = -bv2 i or bv2 i since it is v2 is not a vector...How do i determine its direction using vector methods?
a) Free-fall starting from rest, downwards as positive.
(Common sense) Opposes motion:
b) Free-fall starting from rest, upwards as positive.
The object is moving downwards, hence velocity is negative. To oppose velocity, resistive force points downwards.
However, I got all my directions wrong when taking the upward as positive! I don't know what is wrong with my reasoning!