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Chapter 7 of 13
Revision Notes

Work, Energy, and Simple Machines — Revision Notes

CBSE · Class 9 · Science

Work, Energy, and Simple Machines revision notes for CBSE Class 9 Science: 4 topics in quick points. Part of the CBSE Class 9 Science syllabus.

80 questions80 flashcards8 formulas & key relations5 concepts

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A line graph showing distance on the Y-axis and time on the X-axis, depicting a straight line passing through the origin, representing uniform speed. Includes labels for calculating speed from the slo
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Key Topics to Revise

1

1. Work Done by a Constant Force

  • Work is done only when a force produces displacement in the direction of the force.
  • If force is zero, work is zero.
  • If displacement is zero, work is zero, even if force is applied.
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2. Work-Energy Theorem and Kinetic Energy

  • An object having the capacity to do work is said to possess energy.
  • Work done on an object appears as a change in its energy.
  • The relation between work done and change in energy is called the work-energy theorem.
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3. Potential Energy and Mechanical Energy

  • Potential energy is energy stored by an object due to deformation or due to the relative positions of objects in a system.
  • A stretched rubber band and a compressed spring store potential energy.
  • Two separated magnets store potential energy because of their relative positions.
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4. Power

  • Power is the rate at which work is done.
  • Same work done in less time means greater power.
  • More work done in the same time also means greater power.

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Full Notes

Key Concepts

Work done by a constant forceEnergy is the capacity to doWork done on an object equalsKinetic energy is the energy possessedPotential energy is stored by

Frequently Asked Questions

What are the important topics in Work, Energy, and Simple Machines for CBSE Class 9 Science?
Key topics in Work, Energy, and Simple Machines include Work Done by a Constant Force, Work-Energy Theorem and Kinetic Energy, Potential Energy and Mechanical Energy, Power. Study these first, then practise questions on each for Class 9 exams.
How should I revise Work, Energy, and Simple Machines for Class 9 exams?
Learn the core ideas first, then work through the 80 practice questions on Work, Energy, and Simple Machines. Revise definitions regularly and use flashcards for quick recall before the exam.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

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