Chapter 8 Rational Functions - 8.1 Model Inverse and Joint Variation - 8.1 Exercises - Problem Solving - Page 557: 42a

When the width and length get doubled, the load remains the same.

Here, we have $P=\dfrac{WD^2}{L}$ ...(1) $P'=\dfrac{2 WD^2}{2 L}=\dfrac{WD^2}{L}$ ...(2) This gives: $P=P'$ When the width and length get doubled, the load remains the same.