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Jumper cables are connected from a fresh battery in one car to charge a dead bat

ID: 1577764 • Letter: J

Question

Jumper cables are connected from a fresh battery in one car to charge a dead battery in another car. The figure below shows the circuit diagram for this situation. While the cables are connected the ignition switch of the car with the dead battery is closed and the starter is activated to start the engine. (Let R = 0.950 and Rs = 0.07 .) 0.012 i Starter 12 V 12 V Live battery Dead battery Ignition switch (a) Determine the current in the starter A downward (b) Determine the current in the dead battery A upward (c) Is the dead battery being charged while the starter is operating? O Yes O No O There is not enough information.

Explanation / Answer

I1+I2=I3…………….…………………eq1

12 – 0.01I2 + 0.95I1 – 12 = 0

I1 = (0.01/0.95)I2…….……………..………eq2

12 – 0.95I1 – 0.07I3 = 0

0.95I1 + 0.07I3 = 12……………..……………..eq3

by solving for I2

0.01052632I2 + I2 = I3…………….……………eq4

and

0.01I2 + 0.07I3 = 12……………..……………..eq5

by solving eq4 and eq5

0.01I2 + 0.07(0.01052632I2 + I2) = 12……………..……………..eq5

0.01I2 + 0.07073684I2 =12

I2 = 148.63 A

(a)

I3 = 1.010526321*148.63

I3 = 150.2 A upward

(b)

I1 = (0.01/0.95)*148.63

I1 = 1.56 A downward

(c)

No, dead battery is not charging

current in the branch with the dead battery is upward, it is offering a small amount of power to starter.