looking for worked out please In a popular 80s movie a scien

looking for worked out please

In a popular 80\'s movie, a scientist/tinkerer made a time machine out of a car that traveled back to the year 1955. In order to propel the car back to 1985, the car needed 1.21 Gigawatts of electrical power. In the movie, a bolt of lightning was used. What if we had a capacitor instead ? Let\'s see how big of a capacitor we\'d need! Assuming that all of the required power is expended in 100 ms, and that the capacitor was charged by a 12V car battery, How much capacitance is required ? If the capacitor were made from parallel plates 1mm apart with an insulator whose dielectric constant is 30 between them, how much plate area is needed ? Express your answer in acres. Use 4047 m^2 = 1 acre.

Solution

Capacitance in Farads F = Current I x time t / voltage dV

If the load current is limited by resistors and not a constant current load, the current will drop as voltage reduces, so the above calculation needs to be changed to a I x dT / dVcalculus form where dT tends to zero. This becomes a bit more messy. So, let\'s keep things simple:

For the output case with a 3 Volt drop over 10 seconds, assuming constant currentload, capacitance works out to:

F = 0.03 x 10 / 3 = 0.1 F = 100,000 microFarads.