Understanding physics becomes easier when you practice concepts instead of only reading them. This Class 9 Science Chapter 7 Work Energy and Simple Machines Worksheet with Answers PDF is designed to help students improve their problem-solving skills and revise important topics from the chapter.
This worksheet includes different types of written practice questions based on work, energy, power, kinetic energy, potential energy, conservation of energy, and simple machines. Students can solve conceptual questions, numerical problems, and application-based exercises to check their understanding.
Regular practice with Worksheets helps students strengthen concepts, improve accuracy, and prepare better for exams. These chapter-wise Class 9 Worksheets are useful for revision, homework practice, and self-assessment. Students can also explore more Class 9 Science Worksheets to practice other chapters and build confidence in Science.
Each question in this worksheet follows the latest CBSE Board learning approach and encourages students to apply concepts in different situations instead of memorizing answers.
Download Class 9 Work Energy and Simple Machines Worksheet PDF with Answers
Students can download the Class 9 Science Chapter 7 Work Energy and Simple Machines Worksheet PDF and practice important questions anytime. The worksheet is useful for quick revision, classroom assignments, and exam preparation.
The PDF contains chapter-based questions that help students understand how concepts of work, energy, and simple machines are applied in daily life situations.
Practicing this worksheet will help you:
- Revise important chapter concepts
- Improve numerical-solving ability
- Understand formulas and applications
- Prepare for school tests and exams
- Check your answers with solutions
Download Work Energy and Simple Machines worksheet PDF and start practicing Class 9 Science Chapter 7.
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Class 9 Work Energy and Simple Machines Worksheet Questions
Practice the following Class 9 Science Chapter 7 Work Energy and Simple Machines Worksheet questions to improve your understanding of important physics concepts. Try solving all questions before checking the answer key.
Section A - Concept-Based Questions
1. What is work? Write the conditions required for work to be done.
2. Explain why work done is zero when a person pushes a wall but the wall does not move.
3. Define energy. Write the SI unit of energy.
4. Differentiate between kinetic energy and potential energy.
5. What is power? Write its formula and SI unit.
6. Explain positive work and negative work with examples.
7. What happens to the kinetic energy of an object when its speed increases?
8. State the law of conservation of energy.
9. What is mechanical energy?
10. Why is a stretched rubber band considered to have potential energy?
Section B - Short Answer Questions
11. Explain different forms of energy with suitable examples.
12. Why does a moving vehicle possess kinetic energy?
13. Describe the energy changes taking place when an object falls from a height.
14. How is work related to energy?
15. Why do athletes take a longer run before making a high jump?
16. Explain how machines make our work easier.
17. What is mechanical advantage? Write its formula.
18. Define efficiency of a machine.
Section C - Numerical Practice Questions
19. A force of 50 N moves an object through a distance of 6 m. Calculate the work done.
20. An object of mass 5 kg is moving with a velocity of 4 m/s. Find its kinetic energy.
21. Calculate the potential energy of a 10 kg object placed at a height of 5 m. Take g = 9.8 m/s².
22. A person completes 600 J of work in 20 seconds. Calculate the power used.
23. A machine lifts a load of 400 N using an effort of 100 N. Calculate its mechanical advantage.
24. Find the work done when a force of 25 N moves an object by 8 metres.
25. A body has a mass of 20 kg and moves with a speed of 3 m/s. Calculate its kinetic energy.
26. A motor does 3000 J of work in 60 seconds. Find its power.
Section D - Application-Based Questions
27. A ball thrown upwards slows down as it moves higher. Explain the energy transformation taking place.
28. Why does water stored at a height contain potential energy?
29. A cyclist moving downhill gains speed without pedalling. Explain why this happens.
30. Why does a fast-moving cricket ball have the ability to break glass?
31. Give examples where energy changes from one form to another in daily life.
Section E - Case-Based Questions
Read the case and answer the following questions.
A student throws a ball vertically upwards. During its motion, the energy of the ball keeps changing from one form to another, but the total energy remains constant.
32. Which energy is maximum when the ball reaches the highest point?
33. Which energy is maximum just before the ball reaches the ground?
34. Which law explains this energy conversion?
A simple machine is used to lift a heavy load by applying less effort. Machines help humans perform tasks easily by changing the direction or amount of force.
35. What is the purpose of using simple machines?
36. Define load and effort in a machine.
37. Why is the efficiency of a practical machine always less than 100%?
Class 9 Work Energy and Simple Machines Worksheet Answer Key with Solutions
1. Work is done when force applied on an object causes displacement.
2. Work is zero because there is no displacement.
3. Energy is the capacity to do work. SI unit: Joule.
4. Kinetic energy depends on motion, while potential energy depends on position or condition.
5. Power is the rate of doing work. Formula: P = W/t. Unit: Watt.
6. Positive work happens when force and displacement are in the same direction. Negative work happens when they are opposite.
7. Kinetic energy increases when speed increases.
8. Energy cannot be created or destroyed; it only changes from one form to another.
9. Mechanical energy is the total of kinetic and potential energy.
10. A stretched rubber band stores energy due to its changed shape.
19. Work = Force × Distance
= 50 × 6
= 300 J
20. KE = ½mv²
= ½ × 5 × 4²
= 40 J
21. PE = mgh
= 10 × 9.8 × 5
= 490 J
22. Power = Work/Time
= 600/20
= 30 W
23. Given:
Load = 400 N
Effort = 100 N
Formula:
Mechanical Advantage = Load / Effort
Calculation:
MA = 400 / 100
Mechanical Advantage = 4
24: Given:
Force = 25 N
Distance = 8 m
Formula:
Work = Force × Distance
Calculation:
Work = 25 × 8
Work Done = 200 J
25: Given:
Mass = 20 kg
Velocity = 3 m/s
Formula:
KE = ½mv²
Calculation:
KE = ½ × 20 × 3²
KE = 10 × 9
Kinetic Energy = 90 J
26: Given:
Work = 3000 J
Time = 60 seconds
Formula:
Power = Work / Time
Calculation:
Power = 3000 / 60
Power = 50 W
27: When the ball moves upward, its kinetic energy decreases and changes into potential energy. At the highest point, potential energy becomes maximum.
28: Water stored at a height contains potential energy because of its position above the ground. This stored energy can be converted into other forms of energy.
29: A cyclist moving downhill gains speed because gravitational potential energy changes into kinetic energy, increasing the motion of the cycle.
30: A fast-moving cricket ball has high kinetic energy due to its speed. This energy allows it to do work and break the glass.
31: Examples of energy transformation:
Electric bulb: Electrical energy → Light energy
Falling object: Potential energy → Kinetic energy
Battery: Chemical energy → Electrical energy
32: Potential energy is maximum at the highest point because the height of the ball from the ground is maximum.
33: Kinetic energy is maximum just before reaching the ground because the speed of the ball is highest at that point.
34: The law of conservation of energy explains this conversion. It states that energy changes its form, but the total energy remains constant.
35: The purpose of simple machines is to make work easier by reducing effort, changing the direction of force, or increasing the effect of force.
36: Load is the resistance or weight moved by a machine. Effort is the force applied to operate the machine.
37: The efficiency of a practical machine is always less than 100% because some energy is lost due to friction, heat, and other factors during operation.
Concepts Covered in Work Energy and Simple Machines Worksheet
This worksheet covers all important concepts from Class 9 Science Chapter 7, including:
- Meaning of work
- Conditions required for work
- Positive, negative, and zero work
- Energy and different forms of energy
- Kinetic energy
- Potential energy
- Mechanical energy
- Conservation of energy
- Power and its calculation
- Simple machines
- Load and effort
- Mechanical advantage
- Velocity ratio
- Efficiency of machines
- Real-life applications of energy
These concepts help students build a strong foundation in Physics and improve their ability to solve different types of questions.
Important Formulas Used in Work Energy and Simple Machines Worksheet
Students should remember these important formulas while solving the worksheet:
Work Done
W = Force × Displacement
Kinetic Energy
KE = ½mv²
Potential Energy
PE = mgh
Power
Power = Work Done / Time Taken
Mechanical Advantage
MA = Load / Effort
Efficiency
Efficiency = Output Work / Input Work × 100
Learning these formulas helps students solve numerical questions quickly and accurately.
Common Mistakes Students Should Avoid While Solving This Worksheet
Students often lose marks because of small mistakes. Avoid these common errors:
- Writing answers without proper units
- Confusing mass and weight
- Using the wrong formula
- Forgetting conversion of units
- Mixing kinetic energy and potential energy concepts
- Ignoring direction while calculating work
- Not writing complete steps in numerical questions
- Careful practice can help students improve accuracy and score better.
Learning Outcomes After Solving this Worksheet
After completing this Class 9 Science Work Energy and Simple Machines Worksheet, students will be able to:
- Explain the scientific meaning of work
- Identify different types of energy
- Understand energy transformation examples
- Apply formulas to solve numerical problems
- Explain conservation of energy
- Understand working of simple machines
- Calculate mechanical advantage and efficiency
- Connect Science concepts with real-life examples
