Electric field - find earths electric charge

[XxphysicsxX]

Homework Statement

Measurments indicate that there is a weak electric field of 150 N/C surrounding the Earth that points towards the center of the earth. Determine the absolute value of the electric charge of earth.

Homework Equations

F|e| = ma
|E| = |Fe| / |qt|
|E| = k|qs| / r^2

The Attempt at a Solution

Mass of Earth = (5.9 X 10^24 kg)
radius of Earth = (6.37 X 10^6m)
|E| = (5.9 X 10^24 kg)(9.81 m/s)
|E|= 5.85 X 10^ 28

5.85 X 10^ 28= ((8.99X 10^9)(qs)) / ((6.37 X 10^6m)^2

qs= 2.64 X 10^32

which is not even close to the right answer... its supposed to be 6.77 X 10^5 C

Thankyou in advance!

 

[SammyS]

|E| = k|q| / r²

You are give |E| and the direction of E.

Use Earth's radius for r.

Solve for q.

Figure out the sign of q.