Question

The current going through a car starter is 210 A. If the battery maintains 12 V across the motor, how much electrical energy is delivered to the starter in 10.0 s?25 J250 J2.5 102 J2.5 104 J

Answer 1

In order to determine the energy delivered in the given time, first calculate the electric power of the starter, by using the following formula:

$P=I\cdot V$

where,

I: current = 210 A

V: voltage = 12 V

Replace the previous values of the parameters into the formula for P:

$P=(210A)(12V)=2520W$

where W means watts.

Now, consider that power is the energy delivered per second. Then, for

10.0 s the energy delivered is:

$E=P\cdot t=(2520W)(10.0s)=25200J\approx2.5\cdot10^4J$

Hence, the energy delivered by the starter is approximately 2.5*10^4 J