A2 Daily A Level Physics question
A vertical mass–spring oscillator is used to test a vibration sensor in a lab. With a 1.00 kg mass attached, the period of small vertical oscillations is measured as 1.00 s. The spring is unchanged, and the mass is replaced by a 1.44 kg block. Assuming oscillations remain small and damping is negligible, what is the new period?
Answer
The correct answer is B.
Correct: B — 1.20 s. For a given spring, the period scales with the square root of the mass, so increasing the mass by a factor 1.44 multiplies the period by √1.44 = 1.20, giving 1.00 s × 1.20 = 1.20 s. A confuses the dependence and effectively uses an inverse-square-root scaling (predicting a shorter period when mass increases). B is correct as it uses the correct square-root dependence. C assumes the period is unchanged, ignoring the mass dependence for a mass–spring system. D assumes a linear dependence T ∝ m, overestimating the increase.