Thread: sinusoidal function

need help with this can you provide any light on it.....

The instantaneous value of current, i amp, at t seconds is given by

i= 15 sin (100 pi t + 0.6)

Find
the amplitude
the period
the frequency
the initial phase angle when t =0 expressed in both radians and degrees
the value of i when t=2.5
the time in milliseconds when the current first reaches its maximum value

I need all the help I can get thanks

For

A is the amplitude and is the period, can you answer the first two now?

no sorry can you help some more

Originally Posted by gordonmckee

no sorry can you help some more

you really need to research how sinusoidal graphs are transformed ...

Amplitude ---- 15

Period ---- 2 pi / 100 pi = 1/50

Frequency ---- F=1 / (1/50) = 50Hz

Phase Angle ---- 0.6 rad = (0.6 x (180/pi)) = 34.38deg or 34o 23' leading

I ----15 sin (100 pi 2.5 + 0.6) = 15 sin (786) = 15 x 0.9063 = 13.59Amps

Time ---- 15 = 15 sin (100 pi t + 0.6)

arcsin 15 / 15 = ( 100 pi t + 0.6)

90o or 1.5708rad

100 pi t = 1.5708 - 0.6

t = 0.9708 / 100 pi

t = 0.0031

= 3.1 ms

Am I way off the mark here can someone advise please?

can anyone varify if i'm right on this or not
Thanks

I take it I am on the right track with this then.....

is it nobody knows or not wanting to say that im wrong....please help

Originally Posted by gordonmckee

is it nobody knows or not wanting to say that im wrong....please help

I think your on the right lines, I have just completed this question for my HNC and I have the same answers which I confirmed with my tutor today

Are you at Teeside University?