A body moves in a straight line with constant acceleration

PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

a

. (i) Starting from the basic kinematic relations, derive an expression for the average velocity

\bar{v}

of the body between times

t_1

and

t_2

. (ii) Show that this average velocity equals the instantaneous velocity at any instant within the interval

[t_1, t_2]

only when

a = 0

. (iii) Using your result, explain what distinctive feature of a velocity–time graph indicates that the motion is uniform.