Q.11 Suppose the two photographs, shown in Fig. 13.1 and Fig. 13.2, had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the fastest car.


Answer :

The distance covered by the blue car from one horizontal white strip to another, which is measured by scale is 1.2 cm.

It is given that 1 cm is equivalent to 100 m.

Therefore, 1.2 cm is equivalent to 120 m.

Distance travelled by car = 120 m

Time taken to cover this distance = Time interval between the two photographs = 10 s

Speed = distance/time = 120/10 = 12 m/sec

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