Question

Hi please help with solving the equation to two unknowns here for some reason I'm not getting it. I know the answer I just need the working to understand it please

Answer 1

I have

\[\sum_{}^{} F _{x}=0; 0 = WC \cos 30^{o} - 1.375 Cos \theta \]

Answer 2

\[\sum_{}^{}F _{y}=0; 0=WC \sin30^{o} + 1.375 \sin \theta - 1.5\]

Answer 3

Im stuck at solving for the angle and the WC, my answer is always wrong :(

Answer 4

can u specify which problem is it? 3-12 or 3-13?

Answer 5

sorry 3.13

Answer 6

its been a while since i did this so my memory is vague, i will need ur help if ok?
what's WC?

Answer 7

weight at C :) ty

Answer 8

let me google a bit

Answer 9

u need to have to sum of forces, one over the X axis and the other over the Y axis, let me think more

Answer 10

two sums not 'to'

Answer 11

@miszery
can we say over the X-axis the following?
1.375 cos theta = Wc cos 30

Answer 12

yes

Answer 13

so that's ur 2nd equation
then
Wc = (1.375/cos30) . cosTheta
and can u substitue Wc above in ur first equation to find Theta?

Answer 14

i try to but I get sin theta and cos theta and Im confused how to solve equation with two different trig functions :(

Answer 15

isn't sin = 1/cos or am I wrong?

Answer 16

I forgot the relation but there was one between the 2
I think one is
sin2 + cos2 = 1 ??

Answer 17

i dont know sorry I can't remember the trig identities :S

Answer 18

you may be right i'll have to chech that out

Answer 19

@ganeshie8 hi, do u know much about forces in physics ? kind of stuck on this :(

Answer 20

horizontal components :
\(1.375*\cos(\theta) - C*\cos(30) =0\)

looks good to me

Answer 21

solving the 2 equations over X and Y axis to find Theta and Wc is the hard bit

Answer 22

vertical components :
\(-1.5+ 1.375*\sin(\theta) + C*\sin(30) = 0 \)

Answer 23

do u remember the triangle method for equilibrium ?

Answer 24

that's correct, both @miszery and I got that but can progress any further

Answer 25

let me look it up

Answer 26

me too...

Answer 27

equation I

Wc + 2.75 sinTheta = 3

Answer 28

1.588 cos T + 2.75 sin T = 3 , where T = Theta
what is Theta (T) ?