# Sin curves and currents

1. Sep 30, 2007

### JBemp

1. The problem statement, all variables and given/known data
what is the frequecy F for the alterating current
U(T)=15cos(314t) A

2. Relevant equations
Am really new at this kind of problem but i think 314 is how many times the current rotates or fluxuates in 1 period so the F has to be the distance between waves?

3. The attempt at a solution

15cos(314T)

314/2pi i get 493.23 but i know thats wrong

2. Sep 30, 2007

### arunbg

Are you sure 314/(2pi) is 493.23? Check with your calculator properly

Last edited: Sep 30, 2007
3. Sep 30, 2007

### fikus

$$U\propto cos(\omega t) ~~~~ \omega = 2\pi \nu$$

So you should divide 314 with 2pi, not divide 314 with 2 and then multiply with pi.

4. Sep 30, 2007

### JBemp

ok i see what i did worng forgot the darn ( ) on the calc. man these ( ) always screw me.

thank you both