Which is an example of a situation where a zero is not considered to be a significant digit?
A. When it is to the right of the decimal point, as in 4.20
B. When it is obtained by rounding, as in 3.0
C. When it is between a two non-zero digits, as in 415,505
D. When it comes at the beginning of a number, as in 0.54.

a charge 3q is at the origin, and a charge −2q is on the positive x axis at x=a. part a where on the x-axis would you place a third charge so it would experience no net electric force? enter an expression for the exact answer, which will involve a square-root sign. (do not enter an approximate decimal answer.)

there are no components of a physical goal mentioned on the list of choices that you've provided.