17: Equations Flashcards Preview

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Flashcards in 17: Equations Deck (8)
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1
Q

Stoke’s Law: F =

A

F = 6πνrv
ν (nu) = viscosity of the fluid
r = radius of the object
v = velocity of the object

2
Q

Millikan’s oil drop experiment:
Before the field is switched on
When the drop reaches terminal velocity, 2 forces are equal…

A

mg = 6πνrv

3
Q

Millikan’s oil drop experiment:

Mass of drop:

A

4πr³ρ/3

volume * density ρ

4
Q
Millikan's oil drop experiment:
Equate weight (w/ mass of 4πr³ρ/3) with viscous force.
Rearrange to find r
A

4πr³ρg/3 = 6πνrv
Remember the g for weight!!
so r² = 9νv/2ρg

5
Q

Millikan’s oil drop experiment:
After field is switched on
Which forces are equal

A

qV/d = mg = 4πr³ρg/3

6
Q

Millikan’s oil drop experiment:

Force exerted on a current carrying wire

A
F = BIl
B = magnetic flux density
I = current
l = length (m)
7
Q

Combine I = q/t and v = l/t to get a new equation for current

A

I (current) = qv/l
v = velocity of charged particle
q = charge
l = length

8
Q

For a charged particle travelling in a circular path, which 2 forces are equal….
Rearrange to give r =

A

qvB = mv²/r

r = mv/qB