Question

Jimmy's toy car is powered by four 1.5 volt batteries. The motor has a resistance of 40 ohms.
Yesterday, Jimmy played with the car for 2 hours.
How much energy did the batteries provide during that time?
A) 1.8J
B) 27J
C) 108J
D) 6480J

Answer 1

Assume the 4 cells are connected in series.
\[P(watts)=\frac{V ^{2}}{R}=\frac{6^{2}}{40}\]
Joule = watt-second = \[\frac{6^{2}}{40}\times 2\times 3600=? J\]