Question

A 0.68-kg block is hung from and stretches a spring that is attached to the ceiling. A second block is attached to the first one, and the amount that the spring stretches from its unstrained length quadruples. What is the mass of the second block

Answer 1

Answer:2.04 kg

Explanation:

Given

mass of the first block $m_1=0.68\ kg$

Suppose it brings an extension of x units

When a second mass $m_2$ is attached, then extension quadruples i.e. 4x

For the first case

$m_1g=kx\quad \ldots(i)$

For the second case

$(m_1+m_2)g=k(4x)\quad \ldots(ii)$

divide (i) and (ii)

$\dfrac{m_1}{m_1+m_2}=\dfrac{1}{4}\\\dfrac{0.68}{0.68+m_2}=\dfrac{1}{4}\\\\4\times 0.68=0.68+m_2\\m_2=3\times 0.68=2.04\ kg$