Two negative charges, Q = -50 ? C are placed on the x-axis at x = +0.3 m and x =

Question

Two negative charges, Q = -50 ?C are placed on the x-axis at x = +0.3 m and x = -0.3 m.

Part A

How much energy does it take to assemble these two charges? (in joules)

Part B

You place an unknown charge on the y-axis at y = 0.6 m and find that the electric potential is 0 V at the origin. What is the unknown charge?

Express your answer using three significant figures. (in micro C)

Part C
If you place -5 micro C at the origin, what is the x-component of the force on it from the other three charges? (in Newtons)

Part D
If you place a -5 micro C charge at the origin, what is the y-component of the force on it from the other three charges? (in N)

Explanation / Answer

a) E = k q Q/r = 9.0E9*50.0E-6^2/0.6= 37.5 J

b) so Vnet = v1 + V2 + V3 = sum of k q/r = 9.0E9*(-50.0E-6/0.3 -50.0E-6/0.3 + q/0.6)=0

q=2.0E-4 C = 200 uC

c) so charge at 0.3 and -0.3 cancel so Fx = 0

d) only one at 0.6 matters

so F = k q Q/r^2 = 9.0E9*5.0E-6*2.0E-4/0.6^2= 25 N

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.