An automobile travels eastward with speed (east is positive)

PHYSICS · Single correct · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

An automobile travels eastward with speed

20\,\text{m/s}

(east is positive). It slows down uniformly with a magnitude of acceleration

4\,\text{m/s}^2

. What are the signs of its velocity

v

and acceleration

a

during the slowing down? (a)

v

negative,

a

positive (b)

v

positive,

a

negative (c)

v

positive,

a

positive (d)

v

negative,

a

negative