Answer :
(i) During the first 10 seconds:
Acceleration = Change in velocity / Change in time
From the graph, the velocity changes from 0 m/s to 10 m/s in the first 10 seconds.
So, the change in velocity = 10 m/s - 0 m/s = 10 m/s
The change in time = 10 s - 0 s = 10 s
Acceleration = 10 m/s / 10 s = 1 m/s²
(ii) Between 10 seconds and 35 seconds:
Acceleration = Change in velocity / Change in time
From the graph, the velocity changes from 10 m/s to 0 m/s in the interval from 10 s to 35 s.
So, the change in velocity = 0 m/s - 10 m/s = -10 m/s (negative because the velocity decreases)
The change in time = 35 s - 10 s = 25 s
Acceleration = -10 m/s / 25 s = -0.4 m/s²
(iii) During 35 s to 40 s:
Acceleration = Change in velocity / Change in time
From the graph, the velocity remains constant at 0 m/s during this interval.
So, the change in velocity = 0 m/s - 0 m/s = 0 m/s
The change in time = 40 s - 35 s = 5 s
Acceleration = 0 m/s / 5 s = 0 m/s²
So, the accelerations during the different time intervals are:
(i) During the first 10 seconds: 1 m/s²
(ii) Between 10 seconds and 35 seconds: -0.4 m/s²
(iii) During 35 seconds to 40 seconds: 0 m/s²