_Municipal_Seal.png&w=64&q=75 "Municipality of New Lucena, Iloilo"){kind=small}
The Impulse-Momentum Theorem in the Cry of Jelicuon
Before the Performance: Building the Strength to Change Direction
Direction-change drills during rehearsal are momentum training. Performers start at one side of the stage, build to full speed, and must reverse direction within a set number of beats. Each repetition trains the legs and core to generate larger impulses in shorter time windows. As the choreographer reduces the beat count over weeks of rehearsal, performers must progressively increase their force output to achieve the same momentum change — directly applying the equation J = FΔt = Δp. This progressive overload is why festival performers become noticeably more powerful and agile over the months leading up to the event.
Every timed movement in the war reenactment is governed by the impulse-momentum theorem: J = Δp, where J = FΔt. This equation tells us that to produce a given change in momentum (Δp), a force (F) must be applied over a time interval (Δt). Changing either the force or the time changes the result.
In the fight choreography, performers must reverse direction between positions within a set beat count. The beat provides the time (Δt). The performer's body must supply the force (F). A shorter beat count for the same mass and speed change means the muscles must generate a much larger force.
Δp = m × (vf − vᵢ); F = Δp / ΔtΔp = 55 × (−5 − 5) = 55 × (−10) = −550 kg·m/s; F = 550 / 0.4|Δp| = 550 kg·m/s; F = 1375 NA full reversal doubles the velocity change (from +5 to −5 is a Δv of 10 m/s). The 1375 N required is over twice the performer's body weight — explaining why direction-reversal stunts demand intense conditioning.
During the actual performance, this is exactly what the audience is watching in the fight scene. The instant a performer plants a foot and snaps from charging forward to driving backward, the legs deliver a single, powerful force over the brief time allowed by the beat. That force is the impulse that flips the performer's momentum from one direction to the other — J = FΔt = Δp playing out live, in time with the music. The crisper and faster the choreographer wants the reversal to look, the shorter Δt becomes, and the more force the performer must generate on the spot to land the move on cue.
This is also why airbags in cars reduce injury — they extend the time of the collision, reducing the peak force on the occupant. Similarly, well-padded festival costumes and proper footwear naturally extend impact time, protecting performers during stunts.
After the Performance: Prop Management as Applied Impulse
After the cultural presentation, the propsmen who handled the spinning risers during the show must now wheel those same risers off stage. A riser that was spinning during the performance had angular momentum; brought to rest for transport, propsmen apply braking impulses — gripping and slowing the rotation with controlled force over time. Similarly, when loading chairs into trucks, workers toss light chairs with a brief high-force impulse; heavier stage components are moved with sustained lower-force pushes over longer time intervals to produce the same change in momentum. Every motion in the post-show cleanup is an impulse-momentum calculation in action.