A particle is executing simple harmonic motion with time period 2 s and amplitude 1 cm . If D and d are the total distance and displacement covered by the particle in 12.5 s , then dD is :-
(A)415
(B)25✓ Correct
(C)10
(D)516
Answer: (B)
Solution
With period T=2 s and total time t=12.5 s, the number of complete oscillations is n=Tt=212.5=6.25
The particle completes 6 full oscillations and then a further quarter oscillation.
In one full oscillation (mean → extreme → mean → opposite extreme → mean) it covers a distance 4A; in the extra quarter oscillation, starting from the mean position, it covers a further A to reach an extreme.
Total distance: D=6(4A)+A=25A=25 cm (with A=1 cm)
After 6 complete oscillations the particle is back at the mean position; the additional quarter oscillation carries it to an extreme, so its net displacement from the mean is d=A=1 cm
dD=125=25
JEE Main · 2025 · 24 Jan 2025 · Shift 1 · Single correct option