im almost 1 hour here solving for this sinusodal problem , i really cant solve it, please help me, dont worry this is not an assignment , i need this for my exam next week ,and i need to understand it.
here it is. im sorry i upload it flickr for privacy
heres the problem
http://www.flickr.com/photos/91102274@N08/8360389935/in/photostream
so whats the final answer for both?
billrussell42
Favorite Answer
Assuming "maximum amplitude" means peak current of 20 amps...
Period is 1 ms, so frequency is 1 over that or 1 kHz.
ω = 2πf = 6.28 rad/s
at t = 0, I = 10
I = 20 cos (ωt + φ) = 20 cos (6.28t + φ)
10 = 20 cos (φ)
φ = arccos 0.5 = 60º
I = 20 cos (6.28t + 60º)
?
One cycle in 1ms; 1000 cycles per second.
w =2*pi*1000 radians per second.
i(t) = Imax*(cos w*t + arccos(i(0)/Imax))
= 20*(cos 2*pi*100*t + arccos(10/20))