CBSE CLASS 9 SCIENCE • WORK AND ENERGY
Class 9 Work and Energy Worksheet
NCERT-Style Questions • Numericals • MCQs • Competency-Based Questions • Exam Practice
Class 9 Science
CBSE
NCERT Pattern
Work & Energy
Numericals
MCQs
Class 9 Work and Energy Worksheet – CBSE Science Practice
This Class 9 Work and Energy Worksheet is designed for students preparing the CBSE Class 9 Science chapter Work and Energy. It provides a carefully organised collection of conceptual questions, numerical problems, multiple-choice questions, long-answer questions and competency-based practice.
Students can use this Class 9 Science Work and Energy worksheet for classroom practice, homework, revision, periodic tests and examination preparation. The worksheet covers important concepts such as work done by a force, kinetic energy, potential energy, power, energy transformation, conservation of energy and numerical applications.
The additional questions are designed in an NCERT-style and competency-based format to help students move beyond simple memorisation and apply the concepts of Work and Energy to everyday situations.
Topics covered:
Work • Displacement • Joule • Watt • Kinetic Energy •
Potential Energy • Power • Conservation of Energy •
Energy Transformation • Work-Energy Relationship •
Numericals • MCQs • Assertion-Reason • Case-Based Questions
Quick Work and Energy Formula Revision
W = F × s
K.E. = ½mv²
P.E. = mgh
P = W/t
1 kWh = 3.6 × 106 J
Worksheet Instructions
- Read each question carefully.
- Use SI units in numerical problems wherever required.
- Show the formula and calculation steps for numerical questions.
- Use appropriate scientific terms in theory answers.
- Attempt the competency-based questions after revising the basic concepts.
1 Mark Questions
Q1.
What is the work done when a body is moved horizontally
along a frictionless surface?
Q2.
Define 1 Joule.
Q3.
What is the work done on a body moving in a circular path?
Q4.
When is work said to be done against the force of gravity?
Q5.
Define 1 watt.
Q6.
What is kinetic energy?
Q7.
What will happen to the Kinetic Energy of a body if its
velocity is doubled?
Q8.
Name four units of energy.
Q9.
In a tug of war, one team gives way to other.
What work is being done and by whom?
Concept-Based 1 Mark Questions
Q10.
A student pushes a wall with a large force, but the wall
does not move. What is the work done on the wall?
Give a reason.
Q11.
Which physical quantity is defined as the rate of doing work?
Q12.
Name the form of energy possessed by an object because
of its motion.
Q13.
What happens to the potential energy of an object when
it is raised above the ground?
Q14.
State whether the work done is positive, negative or zero
when friction acts on a moving object.
Q15.
What is the SI unit of energy?
2 Mark Questions
Q16.
Name the transformation of energy involved in these cases:
a. Electric Heater
b. Dynamo
c. Microphone
d. Electric Cell
e. Headphone
f. Photoelectric Cell
g. When Coal burns
Q17.
A person holds a body of mass 20 kg over his head for
10 sec. Has he done any work? Justify your answer.
Q18.
A free falling body stops on reaching the ground.
What happens to its kinetic energy?
Q19.
How are K.E. and momentum related?
Q20.
Is it possible that a body be in accelerated motion under
a force and no work is being done by the force?
Q21.
When an arrow is shot from its bow, it has K.E.
From where does it get the K.E.?
Competency-Based 2 Mark Questions
Q22.
A student carries a school bag while walking on a
horizontal road at constant height. Explain whether the
force exerted by the student on the bag does mechanical
work on the bag.
Q23.
A moving bicycle is brought to rest by applying brakes.
What happens to its kinetic energy? In which forms can
the energy be transformed?
Q24.
A body is lifted vertically upward. Identify the energy
transformation that takes place.
Q25.
Explain why a person can have power greater than another
person even when both perform the same amount of work.
Work and Energy Numerical Problems
Remember:
For numerical questions, write
Given → Formula → Substitution → Calculation → Unit.
Q26.
A force acting on a 20 kg mass changes its velocity from
5m/s to 2 m/s. Calculate the work done.
Q27.
The K.E. of an object of mass m moving with a velocity
of 5m/s is 25 J. What will be its K.E. when its velocity
is doubled? What will be its K.E when its velocity is
increased 3 times?
Q28.
An object of mass 12 Kg is at a certain height above the
ground. If the gravitational P.E. is 480 J, find the height
at which the object is w.r.t the ground (g= 10m/s2).
Q29.
An object of mass 40 kg is raised to a height 5 m above
the ground. What is its P.E.? If object is allowed to fall,
find its K.E. just before touching the ground and also its
K.E. when it is half way down.
Q30.
What is the work done to increase the velocity of car from
36 km/h to 72km/h, if the mass = 1500Kg.
Q31.
A man whose mass is 50 kg climbs up 30 steps of a stair
in 30 s. If each step is 20 cm high, calculate the power
used in climbing stairs.
Long Answer Questions
Q32.
Deduce a formula for K.E of a body.
Q33.
State the law of conservations of energy. Show that when
a body falls from a height the total mechanical energy
remains same.
Application and Reasoning Questions
Q34.
Explain the work–energy relationship. How does the kinetic
energy of a body change when positive work is done on it?
Q35.
Explain the transformation of energy during the free fall
of an object. Why does the total mechanical energy remain
constant when air resistance is neglected?
Q36.
Differentiate between kinetic energy and potential energy.
Give two examples of each.
Multiple Choice Questions
Q37.
P.E. of a person is maximum when he is:
A. standing
B. sitting on a chair
C. sitting on the ground
D. lying down on the ground
Q38.
Work done by moon in moving around earth:
A. +ve
B. –ve
C. zero
D. unknown
Q39.
Work is measured as product of:
A. Force and time
B. Force and displacement
C. Power and displacement
D. Force and acceleration
Q40.
Value of g is:
A. 9.8 m/s
B. 9.8 cm/s2
C. 9.8 m/s2
D. 9.8 cm/s
Competency-Based MCQs
Q41.
A force acts on an object but produces no displacement.
The work done by the force is:
A. Positive
B. Negative
C. Zero
D. Maximum
Q42.
If the velocity of a body becomes three times, its kinetic
energy becomes:
A. Three times
B. Six times
C. Nine times
D. Half
Q43.
Which of the following is a unit of power?
A. Joule
B. Watt
C. Newton
D. Pascal
Q44.
A body has potential energy because of its:
A. Colour
B. Position or configuration
C. Temperature only
D. Shape only
Q45.
Which statement correctly represents conservation of energy?
A. Energy can be created
B. Energy can be destroyed
C. Energy can only be transformed
D. Energy disappears during motion
Assertion and Reason Questions
Choose the correct option:
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Q46.
Assertion (A):
No mechanical work is done on a stationary wall when
a person pushes it.
Reason (R): Mechanical work requires displacement of the point of application of force.
Reason (R): Mechanical work requires displacement of the point of application of force.
Q47.
Assertion (A):
Kinetic energy increases when the speed of an object increases.
Reason (R): Kinetic energy is proportional to the square of velocity.
Reason (R): Kinetic energy is proportional to the square of velocity.
Q48.
Assertion (A):
A body can have acceleration even when the work done by
a particular force is zero.
Reason (R): A force perpendicular to displacement does zero work.
Reason (R): A force perpendicular to displacement does zero work.
Case-Based Questions
Case Study 1: A Falling Object
An object is held at a certain height above the ground and then released. As the object falls, its speed increases. Ignore air resistance for this situation.
Q49(a).
Which form of energy is maximum when the object is at
its initial height?
Q49(b).
What happens to its kinetic energy during the fall?
Q49(c).
What happens to the total mechanical energy when air
resistance is neglected?
Case Study 2: A Student Climbing Stairs
Two students climb the same staircase. Both students reach the same height, but one student reaches the top in less time.
Q50(a).
Is the work done against gravity the same if their masses
and final heights are the same?
Q50(b).
Which student develops greater power?
Q50(c).
Which formula can be used to calculate average power?
Case Study 3: Pushing a Box
A student applies a horizontal force to move a box across a floor. Friction acts opposite to the direction of motion.
Q51(a).
What is the sign of work done by the applied force if it
acts in the direction of displacement?
Q51(b).
What is the sign of work done by friction?
Q51(c).
Why can the net work be different from the work done by
one individual force?
Work and Energy Revision Checklist
- ☐ I can define work and its SI unit.
- ☐ I understand positive, negative and zero work.
- ☐ I know the formula for kinetic energy.
- ☐ I know the formula for gravitational potential energy.
- ☐ I can explain conservation of energy.
- ☐ I can calculate power.
- ☐ I can solve Work and Energy numericals.
- ☐ I can identify energy transformations.
- ☐ I can answer competency-based questions.
Need Help Before Solving This Worksheet?
Revise the complete Class 9 Work and Energy Notes with concepts, formulas, diagrams, derivations and exam-focused explanations.
📘 Read Class 9 Work and Energy NotesSubscribe Us on YouTube
Get more Class 9 Science explanations, worksheets, revision videos, numericals and exam preparation content.
▶ Subscribe Us on YouTubePrint This Worksheet
Want to practise offline? Print this worksheet or save it as a PDF for later revision.