Ch 10 - WORK AND ENERGY9th Science
Scientific Conception of Work
In classical mechanics, what two strict physical conditions must be satisfied for 'Work' to be considered scientifically done on an object?
In classical mechanics, what two strict physical conditions must be satisfied for 'Work' to be considered scientifically done on an object?
The Two Conditions:
- Applied Force: A net external force must act on the object.
- Displacement: The object must be physically displaced along the line of action of the force.
Boundary Condition: If either condition is missing (e.g., pushing a massive rock that does not move, or holding a heavy load while standing perfectly still), the scientific work done is exactly zero.
Prism Memory Hook
FND: Force Needed, Displacement Needed.
Work Equation
Work Equation
State the mathematical formula for work done when a constant force acts in the direction of an object's displacement.
Variables & Units:
- W = Work done (Joules, or )
- F = Constant force applied (Newtons, )
- s = Displacement of the object (metres, )
Conditions/Notes:
- This simplified formula applies strictly when the force and displacement are in the exact same direction.
- Work is a scalar quantity (it has magnitude but no direction).
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Defining One Joule (1 J)
What is the exact physical definition of the SI unit of work, One Joule (1 J)?
What is the exact physical definition of the SI unit of work, One Joule (1 J)?
One Joule is defined as the exact amount of work done on an object when a constant force of 1 Newton displaces it by exactly 1 metre along the line of action of the force.
- Mathematical Equivalence:
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Also in this chapter
27 more cards to study in Prism
- 4Positive vs. Negative Work
- 5The Zero Work Scenario (90° Angle)
- 6The Concept of Energy
- 7Kinetic Energy Equation
- 8Various Forms of Energy
- 9Work-Energy Theorem
- 10Kinetic Energy
- 11Gravitational Potential Energy
- 12The Concept of Potential Energy
- 13Path Independence of Gravity
- 14Conservation in Free Fall
- 15Elastic Potential Energy
- 16Total Mechanical Energy
- 17Power Equation
- 18The Law of Conservation of Energy
- 19Energy Dissipation on Impact
- 20Energy Transformation: The Flashlight
- 21kWh to Joules Conversion
- 22Macro Energy Transformations: Power Plants
- 23The Concept of Power
- 24Kinetic Energy & Momentum Relation
- 25Defining One Watt (1 W)
- 26Horsepower (hp) Conversion
- 27Work Done at an Angle
- 28Average Power
- 29CGS Unit of Work (Erg)
- 30Commercial Unit of Energy
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