---
title: "NCERT Solutions Class 7 Science Measurement of Time and Motion"
url: https://www.swavid.com/science/class/7/chapter/measurement-of-time-and-motion/ncert-solutions
dateModified: 2026-10-07T16:07:36+00:00
---

# NCERT Solutions Class 7 Science Measurement of Time and Motion

This chapter's questions cover the measurement of time, simple pendulums, speed, and uniform versus non-uniform motion. Students calculate speeds, times, and distances, and analyze motion data.

Free PDF (5 pages): https://www.swavid.com/api/seo/pdf/ncert/science/class-7/swavid-ncert-solutions-class-7-science-chapter-8-measurement-of-time-and-motion-9270a8d134.pdf

## Let Us Enhance Our Learning

### Question 1

*3 marks · Numerical*

Calculate the speed of a car that travels 150 metres in 10 seconds. Express your answer in km/h.

**Solution**

1. Given: Distance = 150 m, Time = 10 s.
2. Formula: Speed = Total distance covered / Total time taken.
3. Calculation: Speed = 150 m / 10 s = 15 m/s.
4. Conversion: 15 m/s = 15 × (18/5) km/h = 54 km/h.

**Answer:** 54 km/h

> Common mistake: Forgetting to convert m/s to km/h or using the wrong conversion factor.

### Question 2

*3 marks · Numerical*

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?

**Solution**

1. Given: Distance = 400 m, Runner 1 time = 50 s, Runner 2 time = 45 s.
2. Speed of Runner 1 = 400 m / 50 s = 8 m/s.
3. Speed of Runner 2 = 400 m / 45 s = 8.89 m/s.
4. Difference in speed = 8.89 m/s - 8 m/s = 0.89 m/s.

**Answer:** Runner 2 has a greater speed by 0.89 m/s.

> Common mistake: Rounding off the speed of the second runner incorrectly.

### Question 3

*3 marks · Numerical*

A train travels at a speed of $25\text{ m/s}$ and covers a distance of $360\text{ km}$. How much time does it take?

**Solution**

1. Given: Speed = 25 m/s, Distance = 360 km = 360,000 m.
2. Formula: Total time taken = Total distance covered / Speed.
3. Calculation: Time = 360,000 m / 25 m/s = 14,400 s.
4. Conversion: 14,400 s / 3600 s/h = 4 h.

**Answer:** 4 h

> Common mistake: Failing to convert kilometres to metres before dividing by speed in m/s.

### Question 4

*3 marks · Numerical*

A train travels $180\text{ km}$ in $3\text{ h}$. Find its speed in:
(i) km/h
(ii) m/s
(iii) What distance will it travel in $4\text{ h}$ if it maintains the same speed throughout the journey?

**Part (i)**

1. Speed = 180 km / 3 h = 60 km/h.

Answer (i): 60 km/h

**Part (ii)**

1. 60 km/h = 60 × (5/18) m/s = 16.67 m/s.

Answer (ii): 16.67 m/s

**Part (iii)**

1. Distance = Speed × Time = 60 km/h × 4 h = 240 km.

Answer (iii): 240 km

**Answer:** Speed is 60 km/h or 16.67 m/s, and distance is 240 km.

> Common mistake: Using the wrong conversion factor for km/h to m/s.

### Question 5

*3 marks · Short answer*

The fastest galloping horse can reach the speed of approximately $18\text{ m/s}$. How does this compare to the speed of a train moving at $72\text{ km/h}$?

**Solution**

1. Horse speed = 18 m/s.
2. Train speed = 72 km/h = 72 × (5/18) m/s = 20 m/s.
3. Comparing the two, 20 m/s > 18 m/s, so the train is faster than the horse.

**Answer:** The train is faster than the horse as its speed is 20 m/s compared to the horse's 18 m/s.

> Common mistake: Comparing values without converting them to the same unit.

### Question 6

*3 marks · Short answer*

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.

**Solution**

1. Uniform motion: An object covers equal distances in equal intervals of time; a car on a straight highway with no traffic maintains a constant speed, representing uniform motion.
2. Non-uniform motion: An object covers unequal distances in equal intervals of time; a car in city traffic frequently changes speed due to signals and vehicles, representing non-uniform motion.

**Answer:** Uniform motion involves constant speed (highway), while non-uniform motion involves changing speed (city traffic).

> Common mistake: Confusing uniform motion with simply moving in a straight line.

### Question 7

*3 marks · Numerical*

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.

**Solution**

1. Given table: Time (s) = 0, 10, 20, 30, 50, 70; Distance (m) = 0, 8, 24, 32, 40, 56
2. Since the object is in uniform motion, it covers equal distances in equal intervals of time, meaning speed is constant.
3. Calculate the constant speed using the given point at 10 s: $\text{Speed} = \frac{8\text{ m}}{10\text{ s}} = 0.8\text{ m/s}$.
4. Fill the gap at 20 s: $\text{Distance} = 0.8\text{ m/s} \times 20\text{ s} = 16\text{ m}$.
5. Fill the gap at 50 s: $\text{Distance} = 0.8\text{ m/s} \times 50\text{ s} = 40\text{ m}$ (already given).

**Answer:** The missing distance at 20 s is 16 m.

> Common mistake: Assuming non-uniform rates or dividing incorrectly by time intervals.

### Question 8

*3 marks · Numerical*

A car covers $60\text{ km}$ in the first hour, $70\text{ km}$ in the second hour, and $50\text{ km}$ in the third hour. Is the motion uniform? Justify your answer. Find the average speed of the car.

**Solution**

1. Given: Distance in 1st hour = $60\text{ km}$, 2nd hour = $70\text{ km}$, 3rd hour = $50\text{ km}$.
2. Since the car covers unequal distances in equal intervals of time (hours), the motion is non-uniform.
3. Total distance covered = $60\text{ km} + 70\text{ km} + 50\text{ km} = 180\text{ km}$.
4. Total time taken = $1\text{ h} + 1\text{ h} + 1\text{ h} = 3\text{ h}$.
5. Average speed = $\frac{\text{Total distance covered}}{\text{Total time taken}} = \frac{180\text{ km}}{3\text{ h}} = 60\text{ km/h}$.

**Answer:** Motion is non-uniform; average speed = 60 km/h.

> Common mistake: Averaging the speeds directly $(60+70+50)/3$ without considering total distance and total time.

### Question 9

*3 marks · Short answer*

Which type of motion is more common in daily life—uniform or non-uniform? Provide three examples from your experience to support your answer.

**Solution**

1. Non-uniform motion is more common in daily life than uniform motion.
2. Example 1: A car moving through crowded city traffic speeds up, slows down, and stops.
3. Example 2: A child running in a park changes his speed and direction frequently.
4. Example 3: A train starting from a railway station moves slowly at first, picks up speed, and then slows down before stopping.

**Answer:** Non-uniform motion is more common in daily life, such as a car in city traffic, a child running in a park, or a train starting from a station.

> Common mistake: Giving examples of uniform motion instead of non-uniform motion.

### Question 10

*3 marks · Numerical*

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.

**Solution**

1. Given table data: Total distance covered at 100 s = $60\text{ m}$, Total time taken = $100\text{ s}$.
2. Check uniform speed by calculating distance per 10 s interval: first interval (0 to 10 s) gives $6\text{ m}$, second interval (10 to 20 s) gives $16 - 6 = 10\text{ m}$, which are unequal.
3. Since the object covers unequal distances in equal intervals of time, the speed of the object is non-uniform.
4. Formula: $\text{Average speed} = \frac{\text{Total distance covered}}{\text{Total time taken}}$.
5. Substitution: $\text{Average speed} = \frac{60\text{ m}}{100\text{ s}} = 0.6\text{ m/s}$.

**Answer:** Speed is non-uniform; average speed = 0.6 m/s.

> Common mistake: Taking speed at a single point or dividing incorrectly.

### Question 11

*3 marks · Numerical*

A vehicle moves along a straight line and covers a distance of $2\text{ km}$. In the first $500\text{ m}$, it moves with a speed of $10\text{ m/s}$ and in the next $500\text{ m}$, it moves with a speed of $5\text{ m/s}$. With what speed should it move the remaining distance so that the journey is complete in $200\text{ s}$? What is the average speed of the vehicle for the entire journey?

**Solution**

1. Given: Total distance = $2\text{ km} = 2000\text{ m}$, Total time = $200\text{ s}$.
2. First part: Distance $d_1 = 500\text{ m}$, speed $v_1 = 10\text{ m/s}$. Time taken $t_1 = \frac{500}{10} = 50\text{ s}$.
3. Second part: Distance $d_2 = 500\text{ m}$, speed $v_2 = 5\text{ m/s}$. Time taken $t_2 = \frac{500}{5} = 100\text{ s}$.
4. Remaining distance $d_3 = 2000 - (500 + 500) = 1000\text{ m}$, and remaining time $t_3 = 200 - (50 + 100) = 50\text{ s}$.
5. Speed for remaining distance = $\frac{1000\text{ m}}{50\text{ s}} = 20\text{ m/s}$ and average speed = $\frac{2000\text{ m}}{200\text{ s}} = 10\text{ m/s}$.

**Answer:** Remaining speed = 20 m/s; average speed = 10 m/s.

> Common mistake: Averaging the given speeds directly instead of using total distance and total time.

## Frequently asked questions

### How many questions are there in the NCERT Solutions for Class 7 Science Chapter 8 Measurement of Time and Motion?

The 'Let Us Enhance Our Learning' section contains 11 questions. You can find step-by-step solutions for all of them in the free PDF available on this page only.

### Which topics are covered in the exercise questions of this Class 7 chapter?

The questions cover important concepts like average speed and uniform motion justification, average speed from data tables, and speed, distance, and time relationships. They also test speed calculation, unit conversion, and comparing speeds in different units.

### What are the question types included in the new NCERT book for Class 7 Science Chapter 8?

The chapter includes numerical problems and short answer questions. SwaVid's free PDF on this page provides detailed methods to solve both types easily.

### Which is considered the hardest question type in this Class 7 chapter and how should I approach it?

Numerical problems involving unit conversion and calculating average speed from data tables are often found challenging. To score full marks, first write the given values clearly, apply the correct formula such as $\text{Speed} = \frac{\text{Distance}}{\text{Time}}$, and ensure the final units are consistent.

### Is the free PDF for Class 7 Science Chapter 8 Measurement of Time and Motion available?

Yes, the complete free PDF with detailed step-by-step solutions is available on this SwaVid page. It helps students understand proper answer-writing techniques to score full marks in exams.

## Related pages

- [Class 7 Science chapters](https://www.swavid.com/science/class/7)

Solutions written by SwaVid, a personal AI tutor for Class 6 to 10 Maths and Science. Practise this chapter free: https://www.swavid.com/start/student