a person walks first at a constant speed of 4.90 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.90m/s.
(a) what is her average speed over the entire trip? (in m/s)

The average speed ever the entire trip was 3.9 m/s.

Explanation:

We can calculate the average speed of the person over the full trip as:

s = (4.9 m/s + 2.9 m/s) / 2 = 3.9 m/s

To calculate the average speed we don't need what is the total displacement, but only the speed in each section of the trip (4.9 m/s and 2.9 m/s) and the number of sections of the trip (2 sections).

explanation:

an enlarged virtual image is the answer

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.)