Question

For most species of fish, the mass M (in kg) is related to the body length L (in m) by the power-law relationshipcM=k×L3 where k is a constant. A young fish has a mass of 2.8 kg and a length of 70 cm.

(a) What is the mass in kg of an adult fish whose length is 130 cm? Give the answer to at least 3 significant figures.

(b) What is the length in m of a fish whose mass is 7 kg? Give the answer to at least 3 significant figures.

Answer 1

Mass of adult fish $=\frac{130×2.8}{70}= 5.2kg$

Length in m $=\frac{7×70}{2.8}=175cm=1.75m$