# What is values of q1 and q2? Can you help me?

In the figure two charges are fixed. Another charge Q= -1.89 μC having mass m= 4.00 g is initially at 3.00 cm from each of these two charges and released from the rest.

The initial acceleration of Q= -1.89 μC is 345 m/s^2 and upward and is parallel to the line connecting these two q1 and q2 charges. What is values of q1 and q2?

### 1 Answer

- FiremanLv 71 month agoFavourite answer
BY F = ma

=>F = 4 x 10^-3 x 345

=>F = 1.38 N

Let the forces from q1 & q2 on the Q is F1 & F2 respectively, since it is given that F1x = F2x

=>q1 & q2 are having +ve & -ve charge, Let q1 is having +ve & q2 is having -ve charge

Now let ∠q2q1Q = ∠q1q2Q = θ

=>cosθ = 2.25/3 = 41.41

=>θ = 41.418

=>∠q1Qq2 (let 2α ) = 180 - 2 x 41.41 = 97.18*

=>α = 48.59*

Now Given F1x = F2x

=>kq1Q/(3 x 10^-2)^2 xcosα = kq2Q/(3 x 10^-2)^2 xcosα

=>q1 = q2 = (let q)

Thus F = F1y + F2y

=>1.38 = [kq1Q/(3 x 10^-2)^2] x sinα + [kq1Q/(3 x 10^-2)^2] x sinα

=>1.38 = [2kqQ/(3 x 10^-2)^2] x sinα {as q1 = q2}

=>1.38 = q x [{2 x 9 x 10^9 x 1.89 x 10^-12}/{9 x 10^-4}] x sin48.59*

=>q = 48.68 x 10^-3 C

=>q1 = +48.68 mC & q2 = -48.68 mC