Answer:
13. [tex]f = \frac{360}{d}[/tex]
17. Neither direct variation nor inverse variation.
Step-by-step explanation:
13. The diameter of gear (d) and the force (f) required to make it rotate at a constant rate are inversely proportional.
So, the product of the variables d and f is constant.
Now, for d = 9 inches , f = 40 pounds and the product is 360
And for d = 12 inches , f = 30 pounds and the product is 360
Therefore, the relation between d and f is [tex]f = \frac{360}{d}[/tex]. (Answer)
17. y = -6x relation is neither direct variation nor inverse variation. (Answer)
