Three point charges with values q1 = 8.00 nC , q2 = 3.00 nC , and q3 = 7.00 nC are placed on three consecutive corners of a square whose side measures s = 3.00 m . Point A lies at the fourth corner of the square, diagonally across from q2. Point B lies at the center of the square. What are the values of the electric potential at point A and at point B? How much energy (supplied as work) is required to move a test charge q4 = 2.00 nC from point A to point B? Assume the zero of electric potential is chosen to be.

Given:

q1=8*10-9C

q2=3*10-9C

q3=7*10-9C

S=3m

But electric potential V=kq/r

W=q x change in V

Va=k/r(q1+q2/✓2+q3)

Va=9*10^9/3(8*10^-9+3*10^-9/✓2+7*10^-9)=49.5V

VB=k/0.5r.✓2(q1+q2+q3)

Were r is distance at center given by

r=1/2(r)✓2

VB=9*10^9/0.5*3✓2(8*10^-9+3*10^-9+7*10^-9)=33.9v

Change in = Va-Vb=49.5-33.9=15.6V

Work=r*V=2*10^-9*15.6=3.12×10^-8J

Drag force = 2.20N.

Explanation:

Given data:

Weight of the runner = 60kg

Distance completed by the runner = 5km

Time spent to cover the distance = 17 minutes.

Cross sectional area = 0.72m^2.

Density of air = 1.2kg/m^3.

Solution:

V = d/t

Where d = 5km

t = 17 mins

V = (5*103)/(17*60)

= 5.1m/s

The drag force experienced by a person

Fd = 1/2 p C A v2

= 1/2 * 1.2 * 1 * 0.72 * 5.1

= 2.20N

f = f = Fd / m g

f = 2.20 / (60 * 9.8)

= 3.74*10^-3