# Fixed point charges.

1. Jul 26, 2009

A fixed point charge of +2q is connected by strings to point charges of +q and +4q (see attached diagram), Find the tensions $$T_1$$ and $$T_2$$.

For $$T_2$$, I start summing the forces on the +4q point charge.

$$F_{net,4q}=F_{q}+F_{2q}+T_2$$

$$0=F_{q}+F_{2q}+T_{2}$$

$$T_2=-(F_{q}+F_{2q})$$

Is this the correct vector equation?

#### Attached Files:

• ###### physics problem diagram 2.jpg
File size:
2.4 KB
Views:
80
2. Jul 26, 2009

### Staff: Mentor

That's the right idea. (But I would use T1 and T2 to represent the magnitude of the tension forces.)