Understanding motion becomes easier when students practice different types of questions. This Describing Motion Around Us Class 9 Worksheet is designed to help students improve their concepts and practice important topics from CBSE Board Class 9 Science Chapter 4.
This worksheet includes questions based on distance, displacement, speed, velocity, acceleration, equations of motion and motion graphs. Students can use it for regular practice, homework, revision and exam preparation.
At Shiksha Nation, students can explore more Worksheets created according to the latest CBSE learning approach. These Class 9 Worksheets help learners strengthen their concepts through structured practice. Students can also check more Class 9 Science Worksheets to revise different Science chapters effectively.
The questions below focus on written practice and help students develop better understanding instead of only memorising definitions.
Download Describing Motion Around Us Class 9 Worksheet PDF
Students can download the Describing Motion Around Us Class 9 Worksheet PDF to practice Science Chapter 4 questions anytime. This worksheet is useful for understanding important concepts, improving numerical-solving skills and preparing answers for school exams.
The worksheet contains different types of questions that allow students to check their understanding step by step.
Benefits of this worksheet:
- Covers important concepts from CBSE Class 9 Science Chapter 4
- Includes formula-based numerical questions
- Improves graph interpretation skills
- Helps in quick revision before exams
- Supports regular Science practice
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Topics Covered in Describing Motion Around Us Worksheet
This worksheet covers the important topics of Chapter 4 - Describing Motion Around Us. Students should revise these concepts before attempting the questions.
Topics included:
- Motion and rest
- Reference point
- Distance travelled by an object
- Displacement
- Difference between distance and displacement
- Uniform and non-uniform motion
- Speed and average speed
- Velocity
- Acceleration
- Equations of motion
- Distance-time graphs
- Velocity-time graphs
- Interpretation of motion graphs
Practicing these topics helps students understand how objects move and how different quantities related to motion are calculated.
Describing Motion Around Us Class 9 Chapter 4 Questions
The Class 9 Science Chapter 4 worksheet includes different types of written questions. These questions are arranged from basic concepts to higher-level thinking questions so students can practice step by step.
Section A - Remembering Questions
Answer the following questions:
1. Define motion.
2. What is meant by the reference point of an object?
3. Write the SI unit of distance.
4. Define displacement.
5. What is speed? Write its formula.
6. Name the physical quantity calculated by change in velocity per unit time.
7. Write the SI unit of acceleration.
8. What type of quantity is velocity - scalar or vector?
9. Write the three equations of motion.
10. What does the slope of a distance-time graph represent?
Section B - Understanding Questions
Answer the following questions in detail:
1. Differentiate between distance and displacement.
2. Explain why displacement can be zero even when distance is not zero.
3. What is the difference between speed and velocity?
4. Explain uniform and non-uniform motion with examples.
5. Why is velocity called a vector quantity?
6. Explain the meaning of positive and negative acceleration.
7. How does a velocity-time graph help in studying motion?
8. Why can an object moving with constant speed have changing velocity? Explain with an example.
Section C - Application Questions
Solve the following questions:
1. A car travels 150 km in 3 hours. Calculate its average speed.
2. A person walks 40 m towards east and then returns back to the starting point. Find the total distance and displacement.
3. A train starting from rest reaches a velocity of 30 m/s in 10 seconds. Find its acceleration.
4. A cyclist moves with a speed of 12 m/s for 20 seconds. Calculate the distance covered.
5. A body starts from rest and accelerates uniformly at 4 m/s² for 5 seconds. Find the final velocity.
6. A vehicle slows down from 25 m/s to 5 m/s in 4 seconds. Calculate its acceleration.
7. Explain how the area under a velocity-time graph represents displacement.
8. Draw a distance-time graph for an object moving with uniform speed.
9. A ball moves around a circular path and reaches its initial point. Explain its distance and displacement.
10. Calculate the distance travelled by an object moving with an initial velocity of 5 m/s and acceleration of 2 m/s² for 4 seconds.
Section D - Competency-Based Questions
Answer the following real-life based questions:
1. Rahul goes from his home to school which is 2 km away and returns home through the same path. Find his distance and displacement. Explain your answer.
2. Two cars travel the same distance but take different amounts of time. Which car has greater speed? Explain.
3. A runner completes one full round of a circular track. What will be the displacement after completing the round?
4. A bus moving at constant speed takes a turn on a curved road. Is its velocity changing? Give reason.
5. A student observes a straight line on a distance-time graph. What information can be obtained about the motion of the object?
Describing Motion Around Us Worksheet Answer Key
Students can check their responses with the help of the answer key given below. Complete the worksheet first and then compare your answers to identify mistakes and improve your understanding of motion concepts.
Section A - Remembering Questions Answer Key
1. Motion is the change in the position of an object with time when compared to a reference point.
2. A reference point is a fixed point used to describe the position or motion of an object.
3. The SI unit of distance is metre (m).
4. Displacement is the shortest distance between the initial and final position of an object in a particular direction.
5. Speed is the distance travelled by an object per unit time.
Formula:
Speed = Distance / Time
6. The physical quantity calculated by change in velocity per unit time is acceleration.
7. The SI unit of acceleration is metre per second square (m/s²).
8. Velocity is a vector quantity because it has both magnitude and direction.
9. The three equations of motion are:
v = u + at
s = ut + ½at²
v² = u² + 2as
Where:
u = initial velocity
v = final velocity
a = acceleration
s = displacement
t = time
10. The slope of a distance-time graph represents the speed of an object.
Section B - Understanding Questions Answer Key
1.
| Distance | Displacement |
|---|---|
| Total path covered by an object | Shortest distance between starting and ending point |
| Scalar quantity | Vector quantity |
| Depends on path followed | Does not depend on path |
| Cannot be negative | Can be positive, negative or zero |
2. Displacement can be zero when the initial and final positions of an object are the same. For example, when a person completes one round of a circular track and returns to the starting point, distance is covered but displacement becomes zero.
3.
| Speed | Velocity |
|---|---|
| Distance travelled per unit time | Displacement covered per unit time |
| Scalar quantity | Vector quantity |
| Direction is not required | Direction is required |
4.
Uniform motion occurs when an object covers equal distances in equal intervals of time.
Example: A car moving at a constant speed on a straight road.
Non-uniform motion occurs when an object covers unequal distances in equal intervals of time.
Example: A car moving in traffic.
5. Velocity is called a vector quantity because it includes both the speed of an object and the direction of its motion.
6. Positive acceleration means the velocity of an object increases with time. Negative acceleration means the velocity decreases with time and is also called retardation.
7. A velocity-time graph helps us understand the motion of an object. The slope of the graph represents acceleration, and the area under the graph represents displacement.
8. An object moving with constant speed can have changing velocity if its direction keeps changing. For example, an object moving in a circular path may have constant speed but changing velocity due to continuous change in direction.
Section C - Application Questions Answer Key
1. Average speed = Distance ÷ Time
= 150 ÷ 3
Average speed = 50 km/h
2. Total distance travelled = 40 m + 40 m
Distance = 80 m
Displacement = 0 m
(Initial and final positions are the same)
3. Given:
u = 0 m/s
v = 30 m/s
t = 10 s
Acceleration:
a = (v-u)/t
a = (30-0)/10
Acceleration = 3 m/s²
4. Distance = Speed × Time
= 12 × 20
Distance = 240 m
5. Given:
u = 0 m/s
a = 4 m/s²
t = 5 s
Using:
v = u + at
v = 0 + (4 × 5)
Final velocity = 20 m/s
6. Given:
u = 25 m/s
v = 5 m/s
t = 4 s
a = (v-u)/t
a = (5-25)/4
Acceleration = -5 m/s²
The negative sign shows retardation.
7. The area under a velocity-time graph gives the displacement covered by an object during a given time interval.
8. For an object moving with uniform speed, the distance-time graph is a straight line because distance increases equally with time.
9. When a ball completes one round of a circular path:
Distance = Total length of circular path covered
Displacement = 0
because the starting and ending positions are the same.
10. Given:
u = 5 m/s
a = 2 m/s²
t = 4 s
Using:
s = ut + ½at²
s = (5 × 4) + ½(2)(4²)
s = 20 + 16
Distance travelled = 36 m
Section D - Competency-Based Questions Answer Key
1. Distance travelled:
2 km + 2 km = 4 km
Displacement = 0 km
because Rahul returns to the starting position.
2. The car that takes less time to cover the same distance has greater speed because speed is inversely related to time.
3. After completing one full round of a circular track, displacement is zero because the runner returns to the starting point.
4. Yes, the velocity changes because velocity depends on direction. While taking a turn, the direction changes even if speed remains constant.
5. A straight line on a distance-time graph represents uniform motion. It shows that the object covers equal distances in equal intervals of time.
Common Mistakes Students Should Avoid
While solving Describing Motion Around Us questions, students commonly make small mistakes. Avoid these errors for better accuracy:
- Confusing distance and displacement
- Forgetting SI units in numerical answers
- Using speed and velocity as the same quantity
- Not converting km/h into m/s when required
- Forgetting direction while calculating velocity
- Mixing different equations of motion
- Not understanding the meaning of graph slope
- Checking these points can help students write better answers in exams.
Chapter Revision Checklist
Before completing this worksheet, make sure you can understand these concepts:
☐ I can explain motion and reference point
☐ I know the difference between distance and displacement
☐ I can calculate speed and average speed
☐ I understand velocity and acceleration
☐ I remember all three equations of motion
☐ I can solve basic motion numericals
☐ I can understand distance-time graphs
☐ I can understand velocity-time graphs
☐ I can apply motion concepts in real-life examples
