Question

During air-jet weft insertion, if the diameter of the yarn increases by 20%, then the percentage increase in drag force acting on the yarn would be \(\underline{\hspace{2cm}}\).

Hint:

When dealing with drag forces, remember that the force is proportional to the square of the diameter.

Answer 1

Correct Answer: 20

The drag force on the yarn is proportional to the square of the diameter. Therefore, the percentage increase in drag force is twice the percentage increase in diameter. If the diameter increases by 20%, the drag force increases by: \[ \text{Percentage increase in drag force} = 2 \times 20 = 40%. \] Thus, the percentage increase in drag force is \( 40 \).