Work and Energy Class 9 MCQs help students practice one of the most practical and numerical-based chapters in CBSE Board Class 9 Physics. This chapter explains how force, displacement, and energy are connected in different physical situations. Students learn important concepts like work done, kinetic energy, potential energy, power, and conservation of energy through both formulas and real-life applications.
Many students use the word “work” in daily conversation, but in Physics, work has a completely different meaning. Because of this, students sometimes get confused while solving conceptual and numerical questions. Questions related to sign convention, energy transformation, and power calculations are commonly asked in examinations. Regular practice of Work and Energy Class 9 MCQs helps students improve formula application, calculation accuracy, and conceptual understanding.
These MCQs are prepared according to the latest CBSE and NCERT syllabus. The questions support better revision, strengthen Physics fundamentals, and help students prepare more confidently for school tests, periodic assessments, and final examinations.
Important Concepts Covered in Work and Energy Class 9 MCQs
These Work and Energy Class 9 MCQs cover all major concepts from Chapter 10 of Class 9 Science.
- Work done
- Conditions required for work done
- Positive work
- Negative work
- Zero work
- Energy
- Kinetic energy
- Potential energy
- Mechanical energy
- Law of conservation of energy
- Power
- Commercial unit of energy
- SI units related to work and power
- Numerical questions based on work and energy formulas
Some questions are formula-based while others focus on understanding how energy changes form in practical situations.
Situations Where Work and Energy Are Used in Daily Life
The concepts from this chapter can be connected with many activities that students observe regularly.
- A moving bicycle possesses kinetic energy.
- Water stored at a height has potential energy.
- Electric fans and mixers use electrical energy to perform work.
- Stretching a rubber band stores potential energy.
- Lifting a school bag against gravity requires work to be done.
- Running athletes use energy continuously during motion.
Many objective questions in Work and Energy Class 9 MCQs are based on such practical examples and real-life applications.
Work and Energy Class 9 Chapter 10 MCQs with Answers
Q. Which of the following conditions must be met for work to be considered done in physics?
A) I and II only
B) I, II, and III only
C) I, II, III, and IV
D) II and III only
Answer: B
Explanation: Work is done when a force acts on an object, displacement occurs, and displacement has a component in the direction of force. Acceleration is not necessary.
Q. A coolie lifts a luggage of fifteen kilograms from the ground and puts it on his head one point five metres above the ground. Calculate the work done. Take acceleration due to gravity as ten metres per second squared.
A) Twenty-two point five joules
B) One hundred fifty joules
C) Two hundred twenty-five joules
D) Fifteen joules
Answer: C
Explanation: Work done equals mass multiplied by gravity and height. Fifteen multiplied by ten multiplied by one point five equals two hundred twenty-five joules.
Q. Which scenario represents zero work done?
A) A person pushing a wall that does not move
B) A satellite orbiting Earth in a circular path
C) A coolie carrying luggage horizontally
D) All of the above
Answer: D
Explanation: In all cases, displacement is either zero or perpendicular to the force, so work done is zero.
Q. An object of mass m is moving with constant velocity v. If the mass is doubled and velocity is halved, what happens to its kinetic energy?
A) It remains the same
B) It doubles
C) It halves
D) It quarters
Answer: C
Explanation: Kinetic energy equals one-half multiplied by mass multiplied by velocity squared. After substitution, the new kinetic energy becomes half.
Q. A ten-kilogram object is raised to a height of five metres. If allowed to fall, what will be its kinetic energy halfway down? Assume acceleration due to gravity is ten metres per second squared.
A) Two hundred fifty joules
B) Five hundred joules
C) Zero joules
D) Insufficient information
Answer: A
Explanation: Initial potential energy is five hundred joules. At halfway down, half converts into kinetic energy, giving two hundred fifty joules.
Q. Power is defined as the rate of doing work. What is its SI unit?
A) Joule
B) Watt
C) Newton
D) Kilowatt-hour
Answer: B
Explanation: The SI unit of power is watt, equal to one joule per second.
Q. A motor pump raises five hundred litres of water through a height of twenty metres in fifty seconds. Calculate the power of the pump.
A) One thousand watts
B) Two thousand watts
C) Five thousand watts
D) Four thousand watts
Answer: B
Explanation: Mass of water equals five hundred kilograms. Work done equals five hundred multiplied by ten multiplied by twenty. Dividing by fifty seconds gives two thousand watts.
Q. Which statement about energy transformation is correct?
A) Hydroelectric plants convert electrical energy into potential energy
B) A stretched rubber band converts elastic potential energy into kinetic energy
C) A candle converts light energy into chemical energy
D) A moving car converts kinetic energy into chemical energy
Answer: B
Explanation: A stretched rubber band stores elastic potential energy which changes into kinetic energy when released.
Q. The law of conservation of energy states:
A) Energy can be created but not destroyed
B) Energy can be destroyed but not created
C) Energy can neither be created nor destroyed but only transformed
D) Total energy always increases
Answer: C
Explanation: Energy remains conserved and only changes from one form to another.
Q. An object of mass m is dropped from height h. What is its total mechanical energy just before hitting the ground?
A) Zero joules
B) mgh
C) One-half mv squared
D) Both B and C
Answer: D
Explanation: Mechanical energy remains conserved. Just before impact, potential energy converts completely into kinetic energy.
Q. A light and a heavy object have the same kinetic energy. Which has greater momentum?
A) The light object
B) The heavy object
C) Both same
D) Depends on velocity
Answer: B
Explanation: For equal kinetic energy, momentum is greater for the object with greater mass.
Q. If the velocity of an object is doubled, its kinetic energy becomes:
A) Doubled
B) Halved
C) Four times
D) One-fourth
Answer: C
Explanation: Kinetic energy depends on the square of velocity. Doubling velocity increases kinetic energy four times.
Q. A boy pulls a toy car with a force of ten newtons at an angle of thirty degrees to the horizontal. If the car moves five metres horizontally, what is the work done?
A) Fifty joules
B) Twenty-five joules
C) Forty-three point three joules approximately
D) Eighty-six point six joules approximately
Answer: C
Explanation: Work equals force multiplied by displacement multiplied by cosine theta. Ten multiplied by five multiplied by cosine thirty degrees gives approximately forty-three point three joules.
Q. Which of the following is NOT a form of energy?
A) Heat energy
B) Sound energy
C) Pressure energy
D) Chemical energy
Answer: C
Explanation: Pressure is not classified as a form of energy.
Q. A body of mass two kilograms is thrown vertically upward with an initial velocity of twenty metres per second. What is its potential energy at the highest point?
A) Two hundred joules
B) Four hundred joules
C) Eight hundred joules
D) Zero joules
Answer: B
Explanation: Initial kinetic energy converts completely into potential energy. One-half multiplied by two multiplied by twenty squared equals four hundred joules.
Q. A sixty-kilogram man runs up a staircase forty steps high in ten seconds. Each step is fifteen centimetres high. Calculate the power generated.
A) Three hundred sixty watts
B) Three thousand six hundred watts
C) Nine hundred watts
D) Six hundred watts
Answer: A
Explanation: Total height equals six metres. Work done equals sixty multiplied by ten multiplied by six equals three thousand six hundred joules. Dividing by ten seconds gives three hundred sixty watts.
Q. Which of the following describes negative work done?
A) Force in direction of displacement
B) Force perpendicular to displacement
C) Force opposite to displacement
D) No displacement despite force
Answer: C
Explanation: Negative work occurs when force acts opposite to displacement.
Q. What is the work done by gravitational force when a satellite orbits Earth in a perfect circular path?
A) Positive work
B) Negative work
C) Zero work
D) Depends on speed
Answer: C
Explanation: Gravitational force acts perpendicular to displacement, so work done is zero.
Q. A force of twenty newtons displaces an object by five metres in the direction of force. If the same force is applied for twice the distance, how much more work is done?
A) Fifty joules
B) One hundred joules
C) Two hundred joules
D) One hundred fifty joules
Answer: B
Explanation: Initial work is one hundred joules. Doubling distance gives two hundred joules, so additional work is one hundred joules.
Q. An electric heater of one thousand five hundred watts is used for two hours daily for thirty days. Calculate energy consumed in kilowatt-hours.
A) Ninety kilowatt-hours
B) Forty-five kilowatt-hours
C) One hundred eighty kilowatt-hours
D) Sixty kilowatt-hours
Answer: A
Explanation: Power equals one point five kilowatts. Energy equals one point five multiplied by two multiplied by thirty, giving ninety kilowatt-hours.
Q. What is the relationship between work and energy?
A) Work is capacity to do energy
B) Energy is capacity to do work
C) Work and energy are unrelated
D) Work is energy but energy is not work
Answer: B
Explanation: Energy is defined as the ability or capacity to do work.
Q. A spring is compressed by a force. Which energy is stored in it?
A) Kinetic energy
B) Gravitational potential energy
C) Elastic potential energy
D) Chemical energy
Answer: C
Explanation: Compressed springs store elastic potential energy.
Q. What is the work done by friction when a block slides down an inclined plane?
A) Positive work
B) Negative work
C) Zero work
D) Cannot be determined
Answer: B
Explanation: Friction always opposes motion, so it does negative work.
Q. An object of mass m moves with velocity v. If mass is halved and velocity is quadrupled, what is the ratio of new kinetic energy to original kinetic energy?
A) Two is to one
B) Four is to one
C) Eight is to one
D) Sixteen is to one
Answer: C
Explanation: New kinetic energy equals one-half multiplied by one-half m multiplied by four v whole squared, giving eight times the original.
Q. The work-energy theorem states that net work done equals change in:
A) Potential energy
B) Mechanical energy
C) Kinetic energy
D) Thermal energy
Answer: C
Explanation: Net work done on an object equals the change in kinetic energy.
Q. If a body moves with constant velocity, what is the net work done on it?
A) Positive
B) Negative
C) Zero
D) Depends on velocity
Answer: C
Explanation: Constant velocity means no change in kinetic energy, so net work done is zero.
Q. A person lifts a twenty-kilogram block to a height of three metres and then carries it horizontally for five metres. What is the total work done on the block?
A) Six hundred joules
B) One thousand joules
C) Zero joules
D) Cannot be determined
Answer: A
Explanation: Work during lifting equals twenty multiplied by ten multiplied by three equals six hundred joules. Horizontal carrying adds zero work.
Q. If the power of a machine is one hundred watts, how much time will it take to do five thousand joules of work?
A) Fifty seconds
B) Five hundred seconds
C) Five seconds
D) Zero point zero two seconds
Answer: A
Explanation: Time equals work divided by power. Five thousand divided by one hundred equals fifty seconds.
Q. Which is the commercial unit of electrical energy?
A) Joule
B) Watt
C) Kilowatt-hour
D) Newton-metre
Answer: C
Explanation: Electrical energy for commercial purposes is measured in kilowatt-hours.
Q. A car engine produces fifty kilowatts of power. How much work can it do in one minute?
A) Fifty joules
B) Three thousand joules
C) Three multiplied by ten raised to six joules
D) Fifty thousand joules
Answer: C
Explanation: Work equals power multiplied by time. Fifty thousand watts multiplied by sixty seconds equals three multiplied by ten raised to six joules.
Instructions for Students Before Solving the MCQs
- Revise formulas related to work, energy, and power carefully before attempting numerical questions.
- Read units properly during calculations because unit mistakes are very common in Physics MCQs.
- Understand the difference between kinetic energy and potential energy clearly.
- Pay attention to sign convention in positive and negative work questions.
- Practice formula application instead of memorising only definitions.
- Re-check calculations before selecting the final answer.
- Re-attempt incorrect questions after revision for better understanding.
Sometimes students know the formula correctly but still make mistakes because of incorrect substitution of values.
Common Areas of Confusion in Work and Energy MCQs
Many students lose marks in this chapter because several concepts appear similar during objective questions. Some common confusions are listed below.
- Confusing force with work done
- Mixing kinetic energy with potential energy
- Incorrect understanding of zero work
- Mistakes in power calculations
- Forgetting SI units during numerical questions
- Sign errors in positive and negative work problems
- Incorrect application of conservation of energy
Most mistakes happen when students focus only on formulas without understanding the physical meaning behind the concepts.
Why Practice Work and Energy Class 9 MCQs?
Practicing Work and Energy Class 9 MCQs helps students improve both conceptual understanding and numerical solving skills. Since this chapter combines formulas with practical applications, regular MCQ practice becomes important for proper exam preparation.
- These objective questions help students:
- Improve calculation accuracy
- Strengthen understanding of energy concepts
- Learn formula application more effectively
- Prepare for school exams and tests
- Improve confidence in Physics numericals
Regular practice also helps students identify weak concepts and reduce calculation mistakes during revision.
Conclusion
Practicing Work and Energy Class 9 MCQs regularly helps students strengthen their understanding of work done, energy transformation, power, and conservation of energy. These objective questions improve conceptual clarity, formula application, and numerical accuracy, helping students prepare more effectively for Class 9 Science examinations.