Thanks Pickslides for helping understand these questions.
The last one i need answered is really hard i don't understand it, hope you can help.
a) State the amplitude (A) the period (T) and the frequency (F) for the periodic function - 120sin(100 pi t)V.
b) Through how many degrees does a wheel rotate in 10 ms if its angular velocity is 8 rad/s.
c) Sketch one cycle of the given function showing the values of each variable where the curve crosses the axis. V=50sin(4.2*10^2t)