Q. A massless spring gets elongated by amount $x_1$ under a tension of 5 N. Its elongation is $x_2$ under the tension of 7 N. For the elongation of $(5x_1-2x_2)$, the tension in the spring will be,
A) 39 N
B) 15 N
C) 11 N
D) 20 N
Explanation
[Solution by Dr. Abubacker] $T=kx$ is linear: $T(5x_1-2x_2)=5T_1-2T_2=25-14=11$ N. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.