- #1
LearninDaMath
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Is there such a thing as magnitude of average velocity? If so, is it one of these?
Suppose I have to position vectors. [itex]\stackrel{\rightarrow}{r}= 1_x + 2.2_y[/itex] and [itex]\stackrel{\rightarrow}{r}_2 = 2_x + 0_y[/itex]
And the distance between the vectors is Δ[itex]\stackrel{\rightarrow}{r}= \stackrel{\rightarrow}{r}_1 - \stackrel{\rightarrow}{r}_2[/itex]
([itex]1_{x}+2.2_{y}[/itex]) - ([itex]2_{x}+0_{y}[/itex]) = ([itex]-1_{x}+2.2_{y}[/itex])
Velocity = Δr/Δt ([itex]-1_{x}+2.2_{y}[/itex])/2 = (1/2)[itex]_{x}[/itex] + (2.2/2)[itex]_{y}[/itex]
and so magnitude of the velocity components is 1.2m/s
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However, what if I did this:
magnitude of ([itex]-1_{x}+2.2_{y}[/itex]) is 3.84m
and the velocity is 3.84/2 = 1.92m/s
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OR, if I got the magnitude of each vector first: l[itex]\stackrel{\rightarrow}{r}[/itex]l - l[itex]\stackrel{\rightarrow}{r}[/itex]l = 2.41 - 2 = .41 and then .41/2 = .205m/s
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Which would be correct? And, perhaps, of the approaches that don't work, why not?
Suppose I have to position vectors. [itex]\stackrel{\rightarrow}{r}= 1_x + 2.2_y[/itex] and [itex]\stackrel{\rightarrow}{r}_2 = 2_x + 0_y[/itex]
And the distance between the vectors is Δ[itex]\stackrel{\rightarrow}{r}= \stackrel{\rightarrow}{r}_1 - \stackrel{\rightarrow}{r}_2[/itex]
([itex]1_{x}+2.2_{y}[/itex]) - ([itex]2_{x}+0_{y}[/itex]) = ([itex]-1_{x}+2.2_{y}[/itex])
Velocity = Δr/Δt ([itex]-1_{x}+2.2_{y}[/itex])/2 = (1/2)[itex]_{x}[/itex] + (2.2/2)[itex]_{y}[/itex]
and so magnitude of the velocity components is 1.2m/s
__________________________________________________
However, what if I did this:
magnitude of ([itex]-1_{x}+2.2_{y}[/itex]) is 3.84m
and the velocity is 3.84/2 = 1.92m/s
__________________________________________________
OR, if I got the magnitude of each vector first: l[itex]\stackrel{\rightarrow}{r}[/itex]l - l[itex]\stackrel{\rightarrow}{r}[/itex]l = 2.41 - 2 = .41 and then .41/2 = .205m/s
_________________________________________________
Which would be correct? And, perhaps, of the approaches that don't work, why not?