As you know, if you put two DC voltage sources in series, you can provide a larger voltage to an application. For example, two 1.5V AA batteries in series provides 3V. You can do the same thing with AC voltage, though the situation is more complicated. Suppose you have two AC voltage sources that have the same amplitude and frequency, but are out of phase with one another. In mathematical terms, one of the voltage functions looks like and the other looks like . is referred to as a phase offset and is in radians. If you add those sources together, what's the rms voltage of the resulting signal

While strolling downtown on a saturday afternoon, you stumble across an old car show. as you are walking along an alley toward a main street, you glimpse a particularly stylish alpha romeo pass by. tall buildings on either side of the alley obscure your view, so you see the car only as it passes between the buildings. thinking back to your physics class, you realize that you can calculate the car's acceleration. you estimate the width of the alleyway between the two buildings to be 6 m. the car was in view for 0.6 s. you also heard the engine rev when the car started from a red light, so you know the alpha romeo started from rest 4 s before you first saw it. find the magnitude of its acceleration.