Five equations hide in one trapezium.

Constant acceleration means a straight velocity–time line. Every suvat equation is just a different way of measuring that line — its gradient, its area, or the two combined. Nothing here needs memorising.

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The line climbs from $u$ to $v$ over a time $t$. Its gradient is the acceleration, so $a = \dfrac{v - u}{t}$, which rearranges to the first equation.

The area under a velocity–time graph is the displacement. This area is a trapezium: two parallel sides $u$ and $v$, a width $t$.

Slice the trapezium along the line $v = u$. Below sits a rectangle $u \times t$; above it a triangle of base $t$ and height $v - u = at$, so area $\tfrac12 t \times at$. Measuring down from the top instead gives $s = vt - \tfrac12at^2$.

The last equation is the only one with no picture of its own. Take the first two and eliminate $t$ — the difference of two squares does the rest.

Five letters. Pick the equation missing the one you don't want.

Choosing between them, multi-stage journeys, vertical motion under gravity, and twelve graded exam questions with full worked solutions are waiting.

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