Solving Electrostatic Force Problems: Emergency HW Help

[raikchuuyl]

Homework Statement

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 separation of 8.0x10(to the negative 5th power)

Homework Equations

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



AND

Homework Statement

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 :( please help

 

[raikchuuyl]

Homework Statement

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 separation of 8.0x10(to the negative 5th power)

Homework Equations

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



and

Homework Statement

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 :( please help

ahhhhhh :(

 

[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.