Define work done.
Work done is the product of the magnitude of a force and the displacement of the object in the direction of that force.
What is the general formula for work done when a force acts at an angle θ to the displacement?
Work = F × d × cos(θ), where Fcos(θ) is the component of the force in the direction of motion.
Why is the work done by a frictional force always considered negative?
Because friction acts in the opposite direction to the displacement (θ = 180°), and cos(180°) = -1.
Define the Joule (J) in terms of Newtons and meters.
One Joule is the work done when a force of 1 Newton moves an object by 1 meter in the direction of the force.
Distinguish between Work and Moment of a force in terms of distance.
Work is force multiplied by parallel distance, whereas the Moment is force multiplied by perpendicular distance.
What is the formula for work done by a gas expanding against a constant pressure?
W = PΔV, where P is pressure and ΔV is the change in volume.
When work is done ON a gas, what happens to its volume?
The volume of the gas decreases.
When a gas expands and does work BY itself, what happens to its volume?
The volume of the gas increases.
Define Energy.
Energy is the capacity for doing work.
What is Potential Energy?
It is the energy an object possesses due to its position, which can be released to do work (stored energy).
Define Gravitational Potential Energy (GPE) and provide its formula.
GPE is energy stored due to height; ΔE_p = mgΔh.
What is Elastic Potential Energy (Strain Energy)?
The energy stored in stretched or compressed objects, such as springs.
Define Electrical Potential Energy.
The energy stored when a charge is held in an electric field.
Define Kinetic Energy (KE) and provide its formula.
Kinetic energy is the energy possessed due to motion; E_k = 1/2 mv².
Define Internal Energy.
The sum of the kinetic and potential energy of all molecules within a system in random motion.
How does temperature affect the internal energy of an object?
Higher temperatures increase molecular motion (higher KE), increasing internal energy.
Define Mechanical Energy.
The sum of kinetic energy and potential energy of a body in motion.
Where is chemical energy typically stored?
In food, fuel, and batteries; it is released during chemical reactions.
What is Nuclear Energy?
Energy contained in atomic nuclei, released through fission or fusion.
Give examples of Electromagnetic Energy.
Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, Gamma rays.
How is the derivation of Kinetic Energy linked to the equations of motion?
Using v² = u² + 2as → multiply by 1/2 m → gives KE change = Work done.
State the Law of Conservation of Mechanical Energy.
In absence of external forces (except weight), total mechanical energy remains constant.
Describe the energy transformation in a vibrating pendulum at its extreme position.
At the extreme position, GPE is maximum and KE is zero.
Where is the kinetic energy maximum in a pendulum’s swing?
At the equilibrium position, where GPE is minimum.
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Estimates #130
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Chapter 1 #332
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Chapter 2 #218
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Chapter 3 #133
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Chapter 4 #233
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Chapter 5 #261
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Chapter 6 #250
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Chapter 7 #242
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Chapter 8 #492
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Chapter 9 #143
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Chapter 10 #248
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Physical Quantities and Measurement Techniques Definitions #134
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Mechanics Definitions #1121
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Waves and Superposition Definitions #153
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Electricity Definitions #135
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Nuclear Physics and Fundamental Particles Definitions #134
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All Formulae #1180
