Solving Charged Particles: Mass & Charge

[Forceflow]

Two equally charged particles are held 3.8 10-3 m apart and then released from rest. The initial acceleration of the first particle is observed to be 5.0 m/s2 and that of the second to be 9.0 m/s2. The mass of the first particle is 6.3 10-7 kg.
(a) What is the mass of the second particle?

(b) What is the magnitude of the charge of each particle?

For A, i got 3.5e-7, which is the correct answer.
However,for B, i wasn't sure of what to do.

Do you simply do Mass time Acceleration for each particle. Then add those together to get the F?
After that, you would use
F=kqq/r-squared?

 

[Forceflow]

Does anyone know how to do this problem?

 

[Forceflow]

Can someone help me, please?

 

[Forceflow]

Can anyone do this problem?

 

[Quadruple Bypass]

that seems right, but i don't know about adding the forces

 

[Forceflow]

i just don't know what to use for the force, i can do everything from there. So, really i only need to know what to put in for force.

 

[tim_lou]

the force on the first object is the Coulomb force from the second. Since the question explicitly stated that the charge of the two are equal, you have one equation and one unknown.

 

[Forceflow]

could u show me how to get the force, I'm still not understanding..