Word problem (intermediate Algebra)

Question

The power (P) in an electric circuit is directly proportional to the product of the square of the current (I) and the resistance (R). If the power is 100 watts when the current is 5 amps and the resistance is 4 ohms, find the power when the current is 8 amps and the resistance is 11 ohms.

Answer 1

P = k•I²•R from ^1st sentence.

100 = k(5²)(4)  tells us, after substituting the givens, k = 1.

 

Now P = IR and you're going to substitute I = 8 amperes, R = 11 ohms, thus giving the P, in watts for the situation given in the second part of the 2^nd sentence.