Physics Derivations!!

The LeavyC

How many of these are there? If people could just list the ones they know can come up.

I know theres the resistance ones, (1/Rt = 1/R1 +1/R2 ../ Rt=R1+R2) what else should i learn??!!

Below are all the ones i've been told. Cheers guys.

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v = u + at

s = ut + 0.5at^2

v^2 = u^2 + 2as

F = ma

v= wr

T^2 = (4.pi^2.r^3)/GM

n.lambda = dsinO

R = R_1 + R_2 (resistors in series)

1/R = 1/R_1 + 1/R_2 (resistors in parallel)

F = qvB

a=-w^2s

f=-ks

g = GM/r^2

Cokehead Mother

There are 9.

v = u + at

s = ut + 0.5at^2

v^2 = u^2 + 2as

F = ma

v= wr

T^2 = (4.pi^2.r^3)/GM

n.lambda = dsinO

R = R_1 + R_2 (resistors in series)

1/R = 1/R_1 + 1/R_2 (resistors in parallel)

F = qvB

The LeavyC

Cokehead Mother wrote: »

There are 9.

v = u + at

s = ut + 0.5at^2

v^2 = u^2 + 2as

F = ma

v= wr

T^2 = (4.pi^2.r^3)/GM

n.lambda = dsinO

R = R_1 + R_2 (resistors in series)

1/R = 1/R_1 + 1/R_2 (resistors in parallel)

F = qvB

Yet you gave 10?? lol.. thanks a million though!! i actually know the first 3, id forgotten about them.

cartman444

there also

a=-w^2s
f=-ks

Cokehead Mother

Wait, left out one!

g = GM/r^2

cartman444 wrote: »

there also

a=-w^2s
f=-ks

You know I'm sure I've done a LC question where you had to derive one of those but the syllabus claims we don't need to. Odd.

Peleus

you cant derive F= -kS
its a fundamental law and is the definition of hookes law. how can you derive it?

Cokehead Mother

"Derive the relationship between the acceleration of the sphere and its displacement from a fixed point"

- LC Physics, 2007.

This is the question that I thought required us to derive a = -w^2s, but they only needed you to get as far as a = -(k/m)s for full marks.

And yeah, they can't ask you to derive F = -ks in the same way that they can't ask you prove Newton's second law.

A-Bit-Dodge

Cokehead Mother wrote: »

"Derive the relationship between the acceleration of the sphere and its displacement from a fixed point"

- LC Physics, 2007.

This is the question that I thought required us to derive a = -w^2s, but they only needed you to get as far as a = -(k/m)s for full marks.

And yeah, they can't ask you to derive F = -ks in the same way that they can't ask you prove Newton's second law.

I always only every mess around with F=ma for a while and you get there somehow... and then just say that the elastic constant/the mass of the sphere equals omega squared and done...

If yer struggling and want only a few to learn heres a brief summary...

Equations of motion pg 69 of Real World Physics
v= u+at
v^2= u^2 +2as
s= ut+1(a)t^2
2


Circular Motion pg 139
v= rw(omega) (2006)

Circular Satellite Orbits pg143
T^2= 4pi^2R^3 (2005) pg 143
GM


Diffraction Grating (likely this year) pg211
n(lambda)=dsinX(theta)

Resistance pg259
Series...R(total)=R1 +R2+R3
Parallel...1/R(TOTAL)=1/R1+1/R2+1/R3 (2005)

Current in a magnetic field pg 306
F=qvB (2003)


If I spent as long studying as I do analysing past papers, the A1 would be in the bag!!!

The LeavyC

cheers dodge, thats really handy, i think nearly every1 uses that book!
physics has a really high level of a's. 20%of people last year i think so good luck with it!

cartman444

em i think F=-ks is:
let *= proportional to

F*s
F*-s
F=-ks (introduce a constant to change from * to =

anyway I'm not even sure if its right...our teacher told us it but he's a terrible teacher so.....!!!

mike-gunners

Cokehead Mother wrote: »

There are 9.

v = u + at

s = ut + 0.5at^2

v^2 = u^2 + 2as

F = ma

v= wr

T^2 = (4.pi^2.r^3)/GM

n.lambda = dsinO

R = R_1 + R_2 (resistors in series)

1/R = 1/R_1 + 1/R_2 (resistors in parallel)

F = qvB

how do u derive "n lambda = dsin8"???

Cokehead Mother

http://www.studentxpress.ie/proof1.pdf