Question

i want with steps.....

Answer 1

(a)
Displacement = Area under v-t graph

For t = 0 to t = 5
Area = 0.5 * 5 * 4 = 10 m

For t = 5 to t = 12
Area = 4 * 7 = 28 m

For t = 12 to t = 15
Area = 0.5 * 3 * 4 = 6 m

Total displacement = 10 + 28 + 6 = 44 m
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(b)
Acceleration = Slope of line under v-t graph
Slope is negative for t = 12 to t = 15
Hence, truck is decelerating for last 3 seconds.
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(c)
Average velocity = Total displacement / Total time
= 44 m / 15s
= 2.93 m/s