Answer: k 1 + k 2.
- A k<sub>1</sub> + k<sub>2</sub>
- B k<sub>1</sub> k<sub>2</sub>/(k<sub>1</sub>+k<sub>2</sub>)
- C k<sub>1</sub> - k<sub>2</sub>
- D (k<sub>1</sub> + k<sub>2</sub>)/2
Correct answer: A. k<sub>1</sub> + k<sub>2</sub>
Explanation: Springs in parallel: k<sub>eff</sub> = k<sub>1</sub> + k<sub>2</sub> (both springs stretch/compress by the same amount). In series: 1/k<sub>eff</sub> = 1/k<sub>1</sub> + 1/k<sub>2</sub>.
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.