Need Help On Electrical Potential Energy

[bongopukerat]

I need help on these ?'s. They are very confusing to me. Can someone please help me.
-Here they are:

>Two charges are located along the x-axis. ONe has a charge of 6.4 micro C, and the second has a charge of -3.2 micro C. If the electrical potential energy associated with the pair of charges is -4.1x10 to the -2 J, what is the distance between the charges?

>A charge moves a distance of 2.0 cm in the direction of a uniform electric field having a magnitude of 215 N/C. The electrical potential energy of the charge decreases by 6.9x10 to the -19 J as it moves. Find the magnitude of the charge on the moving particle. (Hint: The electrical potential energy depends on the distance moved in the direction of the field.)

>Two alpha particles (helium Nuclei), each consisting of two protons and two neutrons, have and electrical potential energy of 6.32x10 to the -19 J. What is the distance between these particles at this time?

Thanks!

 

[Sirus]

I'm assuming this is homework and you aren't just doing these for fun, so we need to see you attempt the problems first.