Question

In the figure shown, natural length of the spring $=2\text{m}$. Force constant $k=200\text{N/m}$. find the reading of the spring balance if $A$ is kept at rest and $B$ is displaced of the right by $1\text{m}$. Take $g=10m/s^2$

• A. $10\text{kg}$
• B. $20\text{kg}$
• C. $100\text{kg}$
• D. $200\text{kg}$

Answer 1

The correct option is B $20\text{kg}$

Spring balance reads the sprince force which is given as $F_s=kx$, where $k$ is spring constant or stiffness of the spring and $x$ is the net deformation in the spring.
so, as per the question, net elongation of spring is
$x=1\text{m}$
$\therefore$ $F_s=kx=200\times 1=200N$
$\Rightarrow \text{Equivalent mass}=\frac{200}{g}=20\text{kg}$