Mathematics

Problem

For answers and explanations, turn to Chapter 19. 11. The voltage,

V

, in an electrical circuit is related to the current,

I

, and the resistance,

R

, by the equation

V=I R

. The current is decreasing at

-4 \mathrm{amps} / \mathrm{sec}

as the resistance increases at 20 ohms/sec. How fast is the voltage changing when the voltage is 100 volts and the current is 20 amps?