This is not a homework problem in itself. In my physics homework, I wanted to write the difference of two areas (thus yielding a differential disk) as:
Pi*(r+dr)2-Pi*r2
It reduces to
2*Pi*r*dr+Pi*(dr)2
Now, I seem to recall from a prior class that a quick hand-waving made (dr)2 =...
Homework Statement
A simple pendulum of length (1.0m) and mass (5.0*10^-3 kg) is placed in a uniform electric field that is directed vertically upward. The bob has a charge (-8*10^-6 C). The period of the pendulum is (1.2 s). What are the magnitude and direction of the electric field...