When a test charge q0 = 9 nC is placed at the origin, it experiences a force of 8 times 10-4 N in the positive y direction.

(c) If this force is due to a charge on the y axis at y = 3 cm, what is the value of that charge?

so in a I found E to be 88888.889
in b I found the F on a charge of -4nC to be -3.555e-4

I thought for C I would just use E=kq/(r^2) but it was wrong

To find the value of the charge on the y-axis, we can use Coulomb's law and the given information.

(a) First, let's find the electric field (E) using the equation:

E = F / q0

Given that the test charge q0 = 9 nC and the force F = 8 × 10^(-4) N, we can substitute these values into the equation:

E = (8 × 10^(-4) N) / (9 × 10^(-9) C)

E = 8.889 × 10^4 N/C

(b) Next, let's find the force (F) on a charge of -4 nC using the equation:

F = q * E

Given that the charge q = -4 nC and the electric field E = 8.889 × 10^4 N/C, we can substitute these values into the equation:

F = (-4 × 10^(-9) C) * (8.889 × 10^4 N/C)

F = -3.556 × 10^(-4) N

We have the correct value for the force in part (b).

(c) Finally, let's find the value of the charge on the y-axis using the equation:

F = k * (q0 * q) / r^2

where k is Coulomb's constant, q0 is the test charge, q is the unknown charge at y = 3 cm, and r is the distance between the charges.

We know F = -3.556 × 10^(-4) N, q0 = 9 nC, r = 3 cm, and we need to solve for q.

Rearranging the equation to solve for q, we have:

q = (F * r^2) / (k * q0)

Substituting the given values, we get:

q = ((-3.556 × 10^(-4) N) * (0.03 m)^2) / ((8.99 × 10^9 Nm^2/C^2) * (9 × 10^(-9) C))

q ≈ -4 nC

Therefore, the value of the charge on the y-axis is approximately -4 nC.

To find the value of the charge that is responsible for the force experienced by the test charge, you can use Coulomb's law. Coulomb's law states that the force between two charges is given by F = k * (q1 * q2) / r^2, where F is the force, k is the electrostatic constant (9 x 10^9 Nm^2/C^2), q1 and q2 are the charges, and r is the distance between the charges.

In this case, you have already calculated the force on the test charge (q0) to be 8 x 10^-4 N in the positive y direction and the distance (r) between the charges to be 3 cm. However, you cannot directly use the formula because you don't know the value of the other charge (q).

To solve for q, you can rearrange Coulomb's law equation as follows: q = (F * r^2) / (k * q0).

Substituting the known values, q = (8 x 10^-4 N * (0.03 m)^2) / (9 x 10^9 Nm^2/C^2 * 9 x 10^-9 C) = 0.24 C.

Therefore, the value of the charge responsible for the force experienced by the test charge is 0.24 Coulombs.

forc=Kq2*q0/.03^2

solve for q2

q2=force*.03^2/kq0

c is asking for charge from force