Question

A block of mass $2kg$ is suspended from the ceiling through a massless spring of spring constant $k=100\text{N/m}$. What will be the difference in the elongation of the spring, if another $1kg$ mass is added to the mass of the block?
(Take $g=10m/s^2$)

• A. $0.1\text{m}$
• B. $0.2\text{m}$
• C. $0.3\text{m}$
• D. $0.5\text{m}$

Answer 1

The correct option is A $0.1\text{m}$

For equilibrium,
Spring force = Weight of the block
$k{x}_1=m_{1}g\Rightarrow x_1=\frac{m_{1}g}{k}\Rightarrow \frac{2\left(10\right)}{100}=0.2\text{m}$
Case (2) $x_2=\frac{m_{2}g}{k}=\frac{3\left(10\right)}{100}=0.3\text{m}$
Difference in the elongation $=0.3-0.2=0.1\text{m}$