The speed-time graph of a car is shown in figure given below

Speed-time graph]
(a) Find how far does the car travel in the first 4 second. Shade the area on the graph that represents the distance travelled by the car during the period.
(b) Which part of the graph represents uniform motion of the car ?

Explanation

(a) On the time axis 5 divisions = 2s On the speed axis 3 divisions `= 2 ms ^(-1) therefore 5 xx 3 = 15 ` small squares `= 2 xx 2 ms ^(-1) = 4m`
Total area under the speed-time graph for the first 4 seconds = 60 small squares
`therefore` Distance covered by the car in first 4 seconds `= (60 xx 4)/(15) = 16 m.`
(b) After 6 second the graph represents uniform motion of the car.