Nuclear fusion requires MCQ with Answer and Explanation

Explanation:
a ∝ -x; magnitude maximum when |x| maximum (extremes). At mean position x=0 ⇒ a=0. Velocity maximum at mean position. Memory aid: 'SHM: a max at extremes, v max at center'. Oscillation concept frequently tested in competitive exams to verify SHM characteristics understanding.

Explanation:
K = p²/(2m) => 100 = 2500/(2m) => m = 2500/200 = 12.5 kg.

Explanation:
Elastic PE: U = ½kx² ⇒ k = 2U/x². x = 3 cm = 0.03 m. k = 2×18/(0.03)² = 36/0.0009 = 40000 N/m. Unit conversion critical: cm to m. Memory aid: 'k = 2U/x²; always use SI units'. Tests spring energy formula application with unit conversion, frequently appearing in competitive exams.