Common household electric current is called alternating current because the current alternates direction within the wires. The voltage V in a typical 115-volt outlet can be expressed by the function V(t)=163 sin wt Upper V left parenthesis t right parenthesis equals 163 sine omega t
,
where omega=w

is the angular speed (in radians per second) of the rotating generator at the electrical plant and t is the time measured in seconds. It is essential for electric generators to rotate at precisely 60 cycles per sec.

How many times does the current oscillate in 0.30

sec?__times