Electric Field Problem: Motion of Charges Near Two Fixed Points

[jason.rivera1]

Consider the arrangement of two fixed point charges, equal in magnitude, shown in the figure. Which of the following statements are correct for the initial motion of a third charge if it is released from rest in the vicinity of the two charges shown?

True or False:

A negative charge at point a will accelerate toward the lower-right.
A positive charge at point b will accelerate up.
A negative charge at point e will accelerate up.
A positive charge at point c will accelerate toward the lower-left.
A positive charge at point d will accelerate up.

 

[dnp33]

it might help if you draw electric field lines running from the positive to negative charge to help yourself visualize what is going on.
if you don't know what electric field lines are there is a perfect example of how to draw electric field lines between a positive and negative charge

http://en.wikipedia.org/wiki/File:VFPt_charges_plus_minus_thumb.svg

a positive charge will move in the direction of the arrows, and a negative in the opposite direction.

 

[brucemaster]

A negative charge at point a will accelerate toward the lower-right.
A positive charge at point b will accelerate up.
A negative charge at point e will accelerate up.....these are correct

 

[ngc1333]

A negative charge at point a will accelerate toward the lower-right.
A positive charge at point b will accelerate up.
A negative charge at point e will accelerate up.....these are correct

Not sure about the first one. The electric field line would point straight up at that point. A negative charge would be accelerated straight down. Then it would of course move to the right as well, but the problem asked for the initial motion.