NCERT Class VII Science Solutions: Chapter 13-Motion and Time Part 3

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Question 11:

Suppose the two photographs, shown in , had been taken at an interval of . If a distance of is shown by in these photographs, calculate the speed of the blue car.

As showing in images is a speed of the car

Speed of the Car (Q)

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Answer:

From the, we conclude that the distance covered by blue car is .

As showing in images is a speed of the car

Speed of the Car (Ans)

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So, the distance covered

Question 12:

Fig shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?

This diagram shows time and distance graph

Time and Distance Graph

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Answer:

Vehicle A is traveling longer distance in lesser time as compared to Vehicle B. So, vehicle A is moving faster.

Question 13:

Which of the following distance-time graphs shows a truck moving with speed which is not constant?

This diagram shows four different time-distance graphs

Four Different Time-Distance Graphs

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Answer:

III. Graph is not a straight line, so it shows a truck moving with speed which is not constant.