Q 3.27 The speed-time graph of a particle moving along a fixed direction is shown in Figure. Obtain the distance traversed by the particle between
(b) t = 2 s to 6 s.
What is the average speed of the particle over the intervals in (a) and (b)?
As the speed is increasing in the time interval t = 0 s to t = 5 s the acceleration is positive and can be given by
Speed at t = 2 s is
Speed at t = 5 s is v1 = 15 m s-1
t1 = 5 - 2 = 3 s
Distance travelled in interval t = 2 s to t = 5 s is s1
Acceleration is negative after t = 5 s but has the same magnitude
a2 = -2.4 m s-2
Speed at t = 5 s is u2 = 12 m s-1
t2 = 6 - 5 = 1 s
Distance travelled in this interval can be calculated as follows
Total distance travelled from t = 2 s to t = 6 s is s = s1 + s2
s=25.2+10.8
s=36 m
The average speed over this interval is