JEE Main 2026 Jan 24 Shift 1, Physics Q11: SHM in Spring-Mass System

JEE Main2026Jan 24, Shift 1Physics

A spring of force constant 15 N/m is cut into two pieces. If the ratio of their length is 1:3, then the force constant of smaller piece is____N/m

Solution

For a uniform spring, the force constant is inversely proportional to length: $k ℓ =$ constant.

If the original length is $L$ with $k = 15$ N/m, and the pieces are in ratio $1 : 3$ , the smaller piece has length $L /4$ .

$k_{small} \cdot \frac{L}{4} = 15 \cdot L \Rightarrow k_{small} = 60$ N/m.

Concept behind this question

Concept-wise practice with instant solutions on Fundamenthol.