The graph shows the variation of displacement $d$ with time $t$ for a particle moving with simple harmonic motion of period $T$ - AQA - A-Level Physics - Question 29 - 2019 - Paper 1

In simple harmonic motion, the kinetic energy of the particle varies as a function of displacement. The kinetic energy is maximum when the displacement is zero and decreases to zero when the displacement is at its maximum. Therefore, the correct graph will show a waveform similar to that of the displacement graph but will be positive only in the range where the displacement graph is at its zero crossing.

By analyzing the options:

• Graph A shows a single wave that does not match the required characteristics, as it does not reflect the zero points accurately.
• Graph B is a continuous waveform similar to the displacement graph but shifted, which may not accurately represent the kinetic energy variation.
• Graph C has two peaks, which does not correspond directly because the kinetic energy must not drop to zero at two points within one period where displacement is not zero.
• Graph D matches the requirement as it reflects the oscillation of kinetic energy increasing and decreasing appropriately with the zero crossings of the displacement graph.

Thus, the correct answer is D.