If the path of the particle were to pass through the gray point labeled A, what
ID: 1437929 • Letter: I
Question
If the path of the particle were to pass through the gray point labeled A, what would be its speed at that point?
bod's chames ae id plaionas7.so patide welha char3e 7:s tareeanas ashnan nf 12 8rge, and A 33.91-mC charge is placed 37.65 cm to the left of a 73.73-mC charge, as shown in the figure, and both charges are held stationary. A particle with a charge of-3.551 C and a mass of 42.81 g (depicted as a blue sphere) is placed at rest at a distance 33.89 cm above the right-most charge. If the particle were to be released from rest, it would follow some complicated path around the two stationary charges Calculating the exact path of the particle would be a challenging problem, but even without performing such a calculation it is possible to make some definite predictions about the future motion of the particle. If the path of the particle were to pass through the gray point labeled A what would be its speed VA at that point? Number 3.551 pC m/s 33.89 cm +33.91 mC k-11.30cm K37.65 cm +73.73 mCExplanation / Answer
Using conservation of energy
At initial position particle is at rest hence will have just potential energy and zero kinetic energy
At A it will have both
Hence
KEi +PEi =KEf +PEf
Or change
PEi - PEf = KEf
PEi
qVi
Now distance between the charge on left and blue charge can be calculated using pythagorus theorem
= 50.66cm
Calculating Vi =
k*73.73*10-3/0.3389 + k*33.91*10-3/0.5066 = k*0.2845 V
PEi = -3.551*10-6*k*0.2845 J
Now for PEf = qVf
Distance between right charge at blue charge in final position = 37.65-11.30=26.35cm
Vf = k*73.73*10-3/0.2635 + k*33.91*10-3/0.1130 = k*0.580 V
PEf = -3.551*10-6*k*0.580 J
Using
PEi - PEf = KEf
-3.551*10-6*k*0.2845 - -3.551*10-6*k*0.580 = KEf
9440.65 =KEf
0.5*0.04281v2 = 9440.65
v = 664.1m/s