Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-

Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-57 due to the two positive charges (Q = 7.0 µC) shown. Is your result consistent with Fig. 16-31b?








magnitude at point A= ___ N/C


direction= ___° above the horizon








magnitude at point B= ___ N/C


direction= ___° above the horizon








Figure 16-57: http://i28.tinypic.com/2130i6e.gif


Figure 16-31b: http://i31.tinypic.com/2h4w3e9.gif











Please explain your answer and look up my other open physics questions. If possible, please help on those as well. Thanks!!

Use Coulomb's law to determine the magnitude and direction of the electric field at points A and B in Fig. 16-
Point A


In the x direction


r1=sqrt(25+100)/100 m


r2=sqrt(25+100)/100 m





at Point A the fields in the x cancel.





Let's look at y


C*Q*2*(100^2/125)/sqrt(2) upward


711.8*10^4 N/C in the positive y (90 degrees above the horizon)








Point B





in the x direction


r1=5*sqrt(2)/100 m


r2=sqrt(25+15^2)/100 m





from the left


C*Q*(1/r1^2)/sqrt(2)


from the right


-C*Q*(1/r2^2)*0.15/r2





add them together





Ex=C*Q*((1/r1^2)/sqrt(2)-


(1/r2^2)*0.15/r2)





6509847 N/C in the plus x direction





now the y


from the left


C*Q*(1/r1^2)/sqrt(2)


from the right


C*Q*(1/r2^2)*0.05/r2





add them together


Ey=C*Q*((1/r1^2)/sqrt(2)+


(1/r2^2)*0.05/r2)





9693014.1 upward





The resultant is


sqrt(Ex^2+Ey^2)





11676156.5 N/C





direction is atan(Ey/Ex)


56.11 degrees above the horizontal


________________________-
Reply:Use trig to figure the distances and angles of A %26amp; B from the 2 charges Q.





For each point (A %26amp; B) find the net field along the direction from the charge. Add these fields as vectors at each point by adding the x %26amp; y components of each field. The result will be your answer.





En = k*q/d² (k = 9E9)





There's a lot of busy work here, which why I'm giving general directions only.

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