How long will a fishing line with a stiffness of 500 N / m lengthen when a fish weighing 200 grams

How long will a fishing line with a stiffness of 500 N / m lengthen when a fish weighing 200 grams is lifted vertically upwards.

The force that acts on the line arises as a result of deformation of the body and at the same time it seeks to restore the previous size and shape of the body. It is called the elastic force and is equal to the product of the stiffness coefficient of the body by the change in its length (deformation value): F = k * Δl. In this case, the elastic force is balanced by the gravitational force of the fish F = m * g (m – body mass, g – gravitational acceleration), so we can equate these two forces and express the amount of deformation Δl: k * Δl = m * g; Δl = m * g / k = 0.004 m.