# Homework Help: Hw problems, need help fast !

1. Mar 8, 2005

### Rachmahlerov

hw problems, need help fast plz!

i was absent the day the teacher gave us notes on how to do these problems. it would be sooo helpful if someone could show me how to do some of the following problems, or just offer a brief explanation. thanks so much

1. two hundred years ago, boys were employed on warships and called powder monkeys. their task was to run sacks of black gunpowder from below deck to the cannons on decks. it was ship law that these powder monkeys worked barefoot. why would this be so?

2. if you scuff electrons onto your socks as you walk across the rug, then are your feet negatively or positively charged? what about that area of the rug?

3. a single electron (mass 9.1 x 10^-31 kg) and a single proton (mass 1.7 x 10^-27 kg) within a hydrogen atom are sperated by a distance of 5.3 x 10 ^-11 meters. if these both have the equal, but opposite charges of 1.6 x 10 ^-9 coulombs, then :

a. what is the electrostatic force between them?

b. what is the gravitational force between them?

c. how many times larger is the electrostatic force than the gravitational force?

ill post some more in a minute or so...

2. Mar 8, 2005

### Rachmahlerov

4. two charges qA and qB are seperated by a distance, d, and a exert a force, F, on each other. what will the new force be, in terms of F, if...

a. qA is doubled

b. qA and aB are decreased by half

c. d is tripled

d. d is reduced by half

5. a positive charge of 3 micro-coulombs is placed between two negative charges. determine the force on the positive charge if there is a -2 micro coulomb charge position .050 meters to the north and the other, a -4 micro coulomb charge is .030 meters to the south.

6. two electrons within a carbon atom are separated by 1.5 X 10^-10 meters. using the provided stats from question 3, determine the force between these two electrons.

7. how far apart are two protons if they exert a force of one newton on each other? see question 3 for statistics.

3. Mar 8, 2005

### brewnog

Post your thoughts about how to go about answering the questions; then you'll get some help.

4. Mar 8, 2005

### Rachmahlerov

i have no clue. i missed the day that we got the notes.

5. Mar 8, 2005

### Poobel

OK I know one for sure, for gravitational force use F=G(m1*m2)/(r^2) where m1 and m2 are masses of proton and whatever, r is distace, and G is universal 6.67*10^-11Nm^2/kg^2

6. Mar 8, 2005

### Poobel

For the powder monkeys, I think it would have something to do with either static electricity on their feet, which could blow up whole ship, or something of that sort