Domain: Engineering — Mechanical Engineering
Target concept: A mass-spring-damper system subjected to a brief impact by a mallet

Video generation prompt: A mass-spring-damper system hangs vertically, suspended from a fixed frame above a workbench; a hand strikes the mass block with a rubber hammer briefly and then removes it, so that the mass is no longer subjected to external forces.

Evaluation guide:
(i) Target concept: Underdamped free vibration of a single-degree-of-freedom mass-spring-damper system initiated by impulsive excitation.
Minimum mechanism: Mass must be elastically restrained (spring) and dissipatively coupled (damper) to a fixed support; impact must be transient (duration ≪ natural period); no sustained or secondary forcing after withdrawal.
(ii)Storyline: [Phase 1: Setup] Workbench visible; intact suspended assembly (mass + coiled spring + cylindrical damper) at rest. [Phase 2: Excitation] Hand enters frame holding rubber hammer; hammer contacts mass once with clear impact event (visible deformation/compression at interface); contact ends within ≤1/3 of total visible motion duration. [Phase 3: Isolation] Hand and hammer fully withdraw before mass displacement reverses; mass visibly detached and unsupported. [Phase 4: Response] Mass undergoes ≥3 vertical oscillations with monotonically decreasing peak amplitude; spring coils visibly expand/contract; damper rod moves in/out of housing in sync; no external interaction. [Phase 5: Settling] Motion ceases completely; mass returns to and remains at original equilibrium position. Perspective: Fixed frontal/slightly angled view showing full vertical travel of mass, full length of spring, and damper alignment; no occlusion of critical interfaces (mass-spring, spring-damper, damper-mount).

Manual:
Experimental Procedure
1. Mount a mass-spring-damper system vertically from a rigid workbench.
2. Hold a rubber hammer in hand and strike the mass block once, briefly and perpendicularly.
3. Immediately withdraw the hand and hammer, leaving mass isolated.
Observation of Experimental Phenomena
- Mass displaces at moment of impact.
- Mass then oscillates vertically with diminishing amplitude.
- Spring elongates/compresses synchronously with mass motion.
- Damper motion correlates with spring deformation, suppressing oscillation.
Summary of Experimental Principles
- A brief impact imparts initial kinetic energy.
- System responds via combined spring elasticity (restoring force) and damper dissipation (energy loss).
- Result is underdamped free vibration: decaying harmonic oscillation about equilibrium.

Prompt Grounding rubric:
level_1: No mass-spring-damper assembly appears at all (no mass block, coil spring, or damper cylinder), and no hand or rubber hammer appears; or the apparatus shown is a different kind of system entirely (e.g., a pendulum on a string, or an object simply dropped and left to bounce on the floor).
level_2: The mass, spring, and damper are not shown connected as a single hanging assembly; for instance the hammer strikes an object not clearly attached to the spring/damper, the mass sits on a table rather than hanging, the hand/hammer never actually reaches the mass, or the workbench and the suspended assembly never appear together in the same shot.
level_3: The workbench, a vertically suspended assembly (mass block linked above to a coil spring and to a damper cylinder), a hand holding a rubber hammer, and a strike against the mass are all shown together; but the hammer lingers against the mass longer than a brief tap, or the hand doesn't fully pull away afterward, or the mass is never shown moving on its own once the hand leaves.
level_4: All score 3 elements hold, and additionally the hammer's contact with the mass reads as one short tap rather than a sustained push; the hand and hammer are clearly withdrawn from the mass before it starts swinging on its own; once withdrawn, nothing else touches the mass, spring, or damper for the rest of the shot.
level_5: All score 4 elements hold, and additionally the mass is struck exactly once, with no repeated taps; the hand's withdrawal is unambiguous: it moves clearly out of reach of the mass rather than lingering nearby; the spring and damper read as two recognizably separate, correctly connected parts (spring coils visible along the hanging axis, damper cylinder aligned with it) rather than an ambiguous blob standing in for both.

Scientific and Causal Correctness rubric:
level_1: After the strike, the mass either doesn't move at all, or moves off in one direction and never swings back, or keeps swinging back and forth without ever losing height, or keeps swinging even while the hammer is still touching it.
level_2: The mass oscillates, but the physics is wrong in an obvious way: it starts swinging noticeably before the hammer makes contact, an oscillation that should be decaying instead repeats at the same size cycle after cycle, the spring and damper never visibly stretch/compress or move as the mass swings, or the mass appears to separate from the spring or damper mid-motion.
level_3: Once struck, the mass swings up and down at least twice, with each swing visibly smaller than the one before it; the direction of the first swing matches the direction the hammer pushed it; the mass stays connected to the spring and damper throughout; nothing touches the mass again once the hand withdraws, though the amount of visible decay may still be modest (for example, only two clearly shrinking swings, or the shrinking looking roughly even swing to swing).
level_4: All score 3 conditions hold, and additionally at least three swings are visible, each clearly smaller than the last; the spring's coils visibly stretch and compress in time with the mass's up-and-down motion; the damper's rod or piston shows its own motion moving in step with the spring; the mass comes to rest within a few more swings rather than continuing to oscillate indefinitely.
level_5: All score 4 conditions hold, and additionally the shrinking of each swing looks uneven in a physically sensible way: the drop in swing size between the first and second swing looks larger than the drop between later swings, rather than every swing shrinking by the same fixed amount; the spring and damper move together with the mass throughout, with no visible lag where one clearly moves before the others; by the end of the shot the mass has settled back at its original hanging position and stays there without further drift or swinging.

Spatiotemporal Consistency rubric:
level_1: The mass, spring, or damper vanishes and reappears, or suddenly jumps to a different position; the spring or damper's length changes in one sudden jump rather than a continuous stretch or compression; the hand or hammer blinks in and out of the shot; the lighting flips abruptly between bright and dark with no visible cause; the workbench surface disappears or visibly warps; the mass passes straight through the spring or damper as if they weren't solid.
level_2: A major continuity break occurs: the mass keeps swinging while the hand is still gripping it; the spring stretches or compresses without the mass appearing to move accordingly; the damper's motion doesn't match what the spring is doing; the background or workbench shifts sideways or rotates partway through the shot; the shadows cast by the assembly point in a different direction partway through, as though the light source moved; part of the workbench edge disappears and later comes back.
level_3: The mass, spring, and damper keep a consistent size, shape, and position relative to each other throughout; the motion is continuous, without freezing, skipping, or stuttering; the shadows cast by the hanging assembly keep pointing the same way and stay about the same darkness from start to finish; the workbench stays fully visible and doesn't shift; nothing passes through anything else, though the mass's swinging path may show a little unevenness or the spring/damper axis may drift very slightly out of line.
level_4: All score 3 conditions hold, and additionally the spring's centerline stays lined up with the direction the mass moves throughout the swing; the damper's outer housing stays fixed relative to the workbench while only its internal rod moves; the hand's withdrawal is smooth, without sudden jerks or speed changes; the framing doesn't drift or re-center, so the bench and assembly stay in the same place in the shot.
level_5: All score 4 conditions hold, and additionally the mass, spring coils, and damper housing never stretch or squash out of their normal proportions during the motion; the sequence never repeats or skips a moment of the swing in a way that breaks the flow of motion; no part of the mass, spring, or damper is ever hidden behind the hand or hammer after they've withdrawn; the workbench edges and any background objects stay exactly where they started, confirming the camera never moved.