## Calculate the work needed to move a test charge from point B to D

Calculate the work needed too move a 1.5μC test charge from point B to D.

Can someone just check if I'm thinking correctly?

Do I just use the formula:

W = qEd ?

For the E, I calculate the magnitude and direction of the electric field at B.
And I use 25cm for the distance and q = 1.5μC
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 Recognitions: Gold Member Homework Help W = qEd only works (pun?) if E is uniform. Instead, relate the work to electric potential or electric potential energy.
 Ohhh, I see. So basically, the work needed to bring 1.5μC from a distance (25cm) away to a point 25cm from a charge 75μC? Would it make sense to use this formula? W = q(Va - Vb) W = q[(k*Qa/ra) - (k*Qb/rb)] q = 1.5μC Qa = 75μC Qb = 1.5μC ra(75μC to D) = 25cm rb(B to D) = 25cm

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## Calculate the work needed to move a test charge from point B to D

That's more like it. But, since the charge is being carried from B to D, you'll need to find the potential difference in going from B to D. How would you find the potential at point B due to the two 75 μC charges? Point D?
 ohhh, righttt. So, rewriting it .. W = q(VD - VB) VD = VD1 + VD2 VB = VB1 + VB2 where the distance for VD is 25cm and the distance for VB is 35cm
 Recognitions: Gold Member Homework Help Yes, Good!
 oh, thank goodness lol! Thank youu!