Ranking forces between charged particles

[awilliam_3]

Homework Statement

Two charges with magnitude (Q) experience a force (F) when held a distance apart. Rank from smallest to largest the forces between charges of the following magnitudes (q), held the following respective distances (r) apart. (There may be ties.)

A) q= Q/3 r= R/3
B) q= 2Q r= R/2
C) q= 2Q r= R
D) q= 3Q r= 3R
E) q= Q/2 r= 2R

Homework Equations

E = K [q1 / d^2]

The Attempt at a Solution

I attempted to use E = q1 / d^2 ; inputted values ; for example, for (A): [(Q/3)/(r/3)^2] = 3Q/r^2

I did not get the sequence correct.

 

[rude man]

Don't compute the E field. Use the Coulomb attraction formula instead.

 

[awilliam_3]

Don't compute the E field. Use the Coulomb attraction formula instead.

Oh good grief of course. Thank you.