Chapter 8 Solutions — Measurement of Time and Motion

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1. 1.
   Calculate the speed of a car that travels 150 metres in 10 seconds. Express your answer in km/h.
2. 2.
   A runner completes 400 metres in 50 seconds. Another runner completes the same distance in 45 seconds. Who has a greater speed and by how much?
3. 3.
   A train travels at a speed of 25 m/s and covers a distance of 360 km. How much time does it take?
4. 4.
   A train travels 180 km in 3 h. Find its speed in:

   • (i) km/h
   • (ii) m/s
   • (iii) What distance will it travel in 4 h if it maintains the same speed throughout the journey?
5. 5.
   The fastest galloping horse can reach the speed of approximately 18 m/s. How does this compare to the speed of a train moving at 72 km/h?
6. 6.
   Distinguish between uniform and non-uniform motion using the example of a car moving on a straight highway with no traffic and a car moving in city traffic.
7. 7.
   Data for an object covering distances in different intervals of time are given in the following table. If the object is in uniform motion, fill in the gaps in the table. Time (s): 0, 10, 20, 30, 40, 50, 70. Distance (m): 0, 8, __, 24, 32, __, 56.
8. 8.
   A car covers 60 km in the first hour, 70 km in the second hour, and 50 km in the third hour. Is the motion uniform? Justify your answer. Find the average speed of the car.
9. 9.
   Which type of motion is more common in daily life — uniform or non-uniform? Provide three examples from your experience to support your answer.
10. 10.
    Data for the motion of an object are given in the following table. State whether the speed of the object is uniform or non-uniform. Find the average speed. Time (s): 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100. Distance (m): 0, 6, 10, 16, 21, 29, 35, 42, 45, 55, 60.
11. 11.
    A vehicle moves along a straight line and covers a distance of 2 km. In the first 500 m, it moves with a speed of 10 m/s and in the next 500 m, it moves with a speed of 5 m/s. With what speed should it move the remaining distance so that the journey is complete in 200 s? What is the average speed of the vehicle for the entire journey?