Question

please help!!!

Problem6 a) In the picture below, the 3 charges Q1, Q2 and Q3 are located at positions (-a,0), (a,0) and (0,-d) respectively (The origin is the point halfway between Q1 and Q2.) 2 Consider the special case where Q1, Q3 greater than zero and Q2--Q1 Select true or false for each statement FalseThe electric field at the origin points solely in the positive y direction FalseIf Q3 is released from rest, it will initially accelerate to the right FalseThe force on Q3 due to the other two charges is zero TrueThe electric potential at any point along the y-axis is positive FalseThe electric potential at the origin equals Q3/(4TEod) (Here k- 1/(4jtE))) TrueThe external work done to bring these charges to this configuration (from infinity) was positive True The work required to move Q3 from its present position to the origin is zero Submit Answer Incorrect. Tries 3/6 Previous Tries b) In the previous problem, let Q1 2.40 pC.Q,- 2.90 pC, and Q3°3 30 pC (Note that Q1 and Q2 are different now. The distances are a 1.20 cm and d=2.80 cm Calculate the potential energy of the charge configuration 519.17J Start with charges at infinity, and calculate the work required to bring them to the final configuration, one at a time. Don't forget to convert cm to m Submit Answer Incorrect. Tries 1/6 Previous Tries

Answer 1

a) false- because we can see from the diagram q1 and q2 both are pointing in the positive x direction and q3 is pointing in positive y direction so the resultant will not point in the positive y direction.

b) true- its because if we break down the force in vertical and horizontal direction then only horizontal component remains as the vertical components cancel out each other so since the resultant force will be in +x direction, it will move to the right

c) false-as we have already mentioned that only vertical components of the force cancels put but the horizontal forces add up.

d) true- its because the potential along y axis due to q1 and q2 will be zero, so along y axis the potential will be positive

e) true- as the potential due to q1 and q2 cancels only potential due to q3 will remain

f)false-the external work done is negative since we know the formula W=-qV

g)true- yes because the potential is zero so it means it needs no work for q1 and q2 and for q3 we have already mentioned it will be positive

now in second part we have

first we have to calculate the work done required to bring charge q2 from q1 through a distance 2a

so we have

U1=kq1q2/2a

similarly the work dpne required q3 from q1 and q3 from q2

U2=kq1q3/r1

U3=kq2q3/r2

from the figure and drawing a triagle we can see r=$\sqrt{}$a²+d²

so total potential energy

U=k((q1q2/2a)+q1q3/$\sqrt{}$a²+d²)+q2q3/$\sqrt{}$a²+d²=8.99*10⁹((2.4*10^-6*2.9*10^-6/2*0.012)+(2.4*10^-6*3.3*10^-6/$\sqrt{}$0.012²+0.028²)+(2.9*10^-6*3.3*10^-6/$\sqrt{}$.012²+.028²=7.769 J

so the answer is 7.77 J or 7.8 J or 7.769 J or 8 J