Answer: 2k.
- A 2k
- B k/2
- C k
- D 4k
Correct answer: A. 2k
Explanation: When a spring is cut to half its length, the spring constant doubles to 2k (shorter springs are stiffer).
In SHM, displacement and velocity are 90° out of phase (v is maximum when x=0, and zero when x is extreme), while acceleration is always exactly opposite in sign to displacement, consistent with a = −ω²x.
Concept context
Simple harmonic motion, spring-mass, pendulum, energy in SHM, and resonance.