Question

The current, I, varies inversely to the resistance, R. If the current is 250 milliamperes when the resistance is 5 ohms, find the current when the resistance is 20 ohms. a) 124.5 milliamperes b) 50 milliamperes c) 62.5 milliamperes d) 1250 milliamperes Question 2 (6.25 points) The distance that an object falls varies directly with the square of the time it falls. If an object falls 16 feet in 3 seconds, how long does it take the object to fall 144 feet? a) 7 seconds b) 8 seconds c) 9 seconds d) 27 seconds

Answer 1

1. c) 62.5 mA
2. c) 9 seconds

Explanation:

1. resistance is multiplied by 20/5 = 4, so current is multiplied by 1/4.

(1/4)(250 mA) = 62.5 mA . . . . matches choice C

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2. distance is multiplied by 144/16 = 9, so time is multiplied by √9 = 3. The time it takes to fall 9 times as far is ...

3 × 3 seconds = 9 seconds . . . . matches choice C