Emergency hw help

1. Jun 7, 2010

raikchuuyl

1. The problem statement, all variables and given/known data
When sugar is poured from the box into the sugar bowl, the rubbing of sugar creates a static electric charge that repels the grains. If each of two sugar grains acquires a charge of 3.0x10(to the negative 11th power) at a seperation of 8.0x10(to the negative 5th power)

2. Relevant equations
electrostatic force= (electrostatic constant)(charge 1)(charge 2)/(distance)(2nd power)

AND

1. The problem statement, all variables and given/known data
Each of two hot-air balloons acquires a charge of 3.0x10(to the negative 5th)C on its surface as it travels through the air. How far apart are the balloons if the electrostatic force between them is 8.1x10(to the negative 2nd)N?

I have no idea how to do this :( plz help

2. Jun 7, 2010

raikchuuyl

Re: Emergency hw help SAVE MY GRADE :(

ahhhhhh :(

3. Jun 7, 2010

americanforest

Look carefully at Coulomb's law:

$$\left|\vec{F}_{elec}\right|=\frac{1}{4 \pi \epsilon_{0}}\frac{q_{1}q_{2}}{r^{2}}$$

Just identify the given quantities with the variables in each problem and do some algebra to solve for the unknown.