Question

An ideal spring with spring constant k is hung from the ceiling. The initial length of the spring, with nothing attached to the free end, is 15.0 cm. When an object of mass m is attached to the free end of the spring, the spring stretches to a final length of 30.0 cm. If k = 3.5 N/cm, what is the mass m of the object?

Answer 1

The mass m of the object = 5.25 kg

Further explanation

Given

k = spring constant = 3.5 N/cm

Δx= 30 cm - 15 cm = 15 cm

Required

the mass m

Solution

F=m.g

Hooke's Law

F = k.Δx

$\tt m.g=k.\Delta x\\\\m.10=3.5\times 15\\\\m=5.25~kg$