A car travels along a straight road towards the east

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

Problem

A car travels along a straight road towards the east. East is taken as the positive direction. At

t = 0\,\text{s}

its velocity is

+20\,\text{m/s}

and at

t = 2\,\text{s}

its velocity is

+12\,\text{m/s}

. (i) What is the sign of the average acceleration during this interval? (ii) Is the car speeding up or slowing down? Give a brief reason.