Class 7 Science Curiosity Chapter 8 Measurement of Time and Motion NCERT Solutions f you are looking for Class 7 Science Curiosity Chapter 8 Measurement of Time and Motion NCERT Solutions, you’ve come to the right place. This chapter helps students understand how we measure time, speed, distance, and different types of motion through simple examples and activities.
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1. Calculate the speed of a car that travels 150 metres in 10 seconds. Express your answer in km/h.
Answer:
Distance = 150 m
Time = 10 s
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?
Answer:
First runner:
Distance = 400 m
Time = 50 s
Second runner:
Distance = 400 m
Time = 45 s
Difference in their speeds = 8.89 − 8 = 0.89 m/s.
Therefore, the second runner is faster than the first runner by 0.89 m/s.
3. A train travels at a speed of 25 m/s and covers a distance of 360 km. How much time does it take?
Answer:
Speed = 25 m/s
Distance = 360 km = 360 × 1000 m = 3,60,000 m
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?
Answer:
Distance = 180 km
Time = 3 h
(iii) Distance travelled in 4 h:
Distance = Speed × Time = 60 × 4 = 240 km.
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?
Answer:
Speed of the horse = 18 m/s
Speed of the train = 72 km/h
Difference in speed = 20 − 18 = 2 m/s
Therefore, the train is faster than the horse by 2 m/s.
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.
Answer:
• Uniform Motion:
When an object covers equal distances in equal intervals of time, it is said to be in uniform motion.
Example: A car moving on a straight highway with no traffic covers equal distances in equal time intervals. Hence, it is in uniform motion.
• Non-uniform Motion:
When an object covers unequal distances in equal intervals of time, it is said to be in non-uniform motion.
Example: A car moving in city traffic slows down and speeds up repeatedly, covering unequal distances in equal time intervals. Hence, it is in non-uniform motion.
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.
Answer:
For uniform motion, the object covers equal distances in equal intervals of time.
So, in every 10 seconds, it covers 8 m.
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.
Answer:
Since the car is covering unequal distances in equal intervals of time, the motion is non-uniform.
Total distance = 60 + 70 + 50 = 180 km.
Total time = 3 h
Therefore, the average speed of the car is 60 km/h.
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.
Answer:
Non-uniform motion is more common in our daily life because most objects do not move with a constant speed. Their speed keeps changing due to various factors like traffic, obstacles, or turns.
Examples:
1. A car moving on a busy road slows down and speeds up frequently.
2. A cyclist riding on uneven roads changes speed and direction often.
3. A child playing in a playground runs, stops, and changes direction.
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.
Answer:
The distances covered are not equal in each 10-second interval. Therefore, the motion is non-uniform.
Therefore, the average speed of the object is 0.6 m/s.
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?
Answer:
Total distance = 2 km = 2000 m
Total time = 200 s
The vehicle covers:
First 500 m at 10 m/s.
Next 500 m at 5m/s.
Total time for the first and second parts = 50 + 100 = 150 s.
Total distance covered in the first two parts = 500 + 500 = 1000 m.
Therefore,
Remaining distance = 2000 – 1000 = 1000 m.
Remaining time = 200 – 150 = 50 s.
At schoollearners.in/, we provide free, accurate, and easy-to-understand NCERT Solutions prepared according to the latest CBSE syllabus. Our solutions are written in simple language so that every student can understand the concepts quickly and score better in exams.
What You’ll Learn in Chapter 8
- Measurement of time
- Types of motion
- Distance and speed
- Uniform and non-uniform motion
- Solved NCERT questions with detailed explanations
Whether you’re completing your homework, revising for exams, or clearing your concepts, schoollearners.in/ offers the best learning resources for Class 7 students.
Class 7 Science Curiosity Chapter 8 Measurement of Time and Motion NCERT Solutions, notes, important questions, MCQs, worksheets, and study materials—all available for free.