I need help with this question below. We (me and classmates) tried it but we just couldn't get the right answer. Thanks in advance!



A point charge +8.75 µC is glued down on a horizontal frictionless table. It is tied to a point charge −6.50 µC by a light, nonconducting wire of length 2.50 cm. A uniform electric field of magnitude 1.85×10^8 N/C is directed parallel to the wire.



(a) Find the tension in the wire.

(b) What would the tension be if both charges were negative?

Homework? You want us to do your homework?!

This ain't Yahoo! Answers.

wot, its summer.

Long time since I did any physics ...
But I think you should first find individual force to each point charge (because of electrical field) F=Q*E think
and then force between two charges (F=k*Q1*Q2/r^2)
check equtions, its possible that I missed something

I thought it's Scawen asking for help with tire physics.

Quote from DANIEL-CRO :

But I think you should first find individual force to each point charge (because of electrical field) F=Q*E think
and then force between two charges (F=k*Q1*Q2/r^2)

Pretty much this. The point charges interact both with the external electric field and with each other. The total force acting on the wire is therefore a sum of field<->C1, field<->C2 and C1<->C2.

I've planned to study physics in University. Learned to drink beer instead.

Maybe BlueFlame can offer his mathematic advice

Instructions unclear, got **** stuck.

Tension would depend on the wires personal relationships at the time, these could be extreme if the wire has discovered the ability to create a frictionless table.

This could be a huge scientific breakthrough so there could be additional tension ( 'Z' say ) that this invention could have created.

Therefore before we can have a corrected answer, we must establish the value of Z.

Z=5

Sounds good.

source: I've done math.