(a)a = (v − u) / t, with u = 0.

(b)Use s = ½(u + v)t for uniform acceleration.

(c)A straight line starting at the origin (v = 0) and rising with constant positive gradient to (8.0 s, 24 m/s) — the gradient represents the acceleration.

(a)v = u + gt, with u = 0.

(b)s = ½gt².

(a)Distance = area under the velocity-time graph: a rectangle (constant speed) plus a triangle (deceleration).

(b)Average speed = total distance ÷ total time.

(a)Speed is a scalar (magnitude only); velocity is a vector (magnitude AND direction).

(b)Average speed uses total distance travelled (400 m); average velocity uses displacement, which is zero since the runner returns to the start.

(a)v = u + at.

(b)s = ut + ½at².

(a)Rearrange v² = u² + 2as with u = 0.

(a)a = (v − u)/t.

(a)Area under a velocity-time graph = distance. This is a trapezium: ½(v₁+v₂)×t.

(a)When two objects move toward each other, their speeds relative to one another add together.

(a)Average speed is the total distance divided by total time for the whole journey; instantaneous speed is the speed at one specific moment. They differ whenever speed is changing during the journey — e.g. a car's average speed over a trip with traffic stops is lower than its instantaneous speed while cruising on a clear motorway.