Constant acceleration (SUVAT) · Year 13
In Year 13 you learn: vertical motion under gravity and velocity–time graphs.
When acceleration is constant, five quantities describe straight-line motion: displacement s, initial velocity u, final velocity v, acceleration a and time t. Five equations link them. Each one leaves out one quantity, so pick the one that fits what you know.
Key facts
- v = u + at
- s = ut + 1/2at^2, and s = vt − 1/2at^2
- s = ((u + v)/2)t
- v^2 = u^2 + 2as
- Choose a positive direction. Anything in the other direction is negative. In free fall, a = −9.8 m/s² if up is positive.
- On a velocity–time graph, gradient = acceleration and area = displacement. If acceleration varies, use calculus: v = ds/dt, a = dv/dt and s = ∫ v dt.