Question

A block of mass $16kg$ is moving on a frictionless horizontal surface with velocity $4m/s$ and comes to rest after pressing a spring. If the force constant of the spring is $100N/m$ then the compression in the spring will be:

• A. $3.2m$
• B. $1.6m$
• C. $0.6m$
• D. $6.1m$

Answer 1

The correct option is B $1.6m$

$1/2k{x}^2=1/2m{v}^2$
$1/2\times 100\times x^2=1/2\times 16\times {\left(4\right)}^2$
$50\times x^2=256/2$
$x^2=128/50$
$x^2=2.56$
$x=1.6$
so, the spring is compressed $1.6m.$

Hence,

option $\left(B\right)$ is correct answer.