Question

• An object moves in a straight line, starting from
rest. There are two stages in the journey:
(a) it gains speed uniformly for 2.0s and
attains a speed of 8.Oms":
(b) it continues at this speed for a further 1.5s.
Draw a sketch-graph of speed against time.
Find (i) the acceleration in stage (a);
(ii) the acceleration in stage (b);
(iii) the total distance moved during stage:
(a) and (b).​

Answer 1

(i)The acceleration in stage (a) = slope of OA, that is

\frac{AD}{OD}  = \frac{8}{2}  = 4mx^{-2}

(ii) The acceleration at stage (b) =0, since there speed was not changing