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Homework Statement
Two 2.0mm diameter beads, C and D, are 9.0mm apart, measured between their centers. Bead C has mass 1.0g and charge 2.5nC . Bead D has mass 1.5g and charge -1.0nC .
K= 9*10^9 Nm^2/C^2
Vinitials =0
mass of C= 1 g
mass of D= 1.5 g
charge of C = 2.5nC
charge of D = -1nC
distance r between them= 9mm
Homework Equations
a) If the beads are released from rest, what is the speed vc at the instant the beads collide?
b) If the beads are released from rest, what is the speed vd at the instant the beads collide?
The Attempt at a Solution
I start by setting up my diagram of the two beads lying on the x-axis. They are 9mm apart from the center, We know initial velocities of both are zero. So I decided to use the conservation of energies formula. Kintial +Uinitial = Kfinal + Ufinal
C: 1/2mvi^2 + (K*C*D)/rinitial = 1/2mvf^2 + (K*C*D)/rfinal
Both Initial Kinetic is zero since they start as rest, as well as Final potential because the distance between them would be zero
So I have (K*C*D)/rinitial = 1/2(mvf^2)
But we have to take into account the kinetic energy of Bead D as well. When doing a similar problem I was told that both Final Kinetic energies must be added. But I would have two unknowns. Both vfinals. I don't know where to go from here. Any hint?
Thanks