5. WORK, ENERGY AND POWER
Key concepts explored include the definitions and interrelations of work, energy, and power, emphasizing their scalar nature and the principles governing their calculations. The chapter examines work done by both constant and variable forces, along with the work-energy theorem and its implications for kinetic and potential energy. The overall theme centers on the conservation of mechanical energy and the nature of collisions.
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What we have learnt
- Work is defined as the product of the force applied and the displacement in the direction of the force.
- Energy exists in various forms, primarily kinetic and potential, and transitions between these forms adhere to the conservation of mechanical energy principle.
- Collisions can be elastic or inelastic, with momentum conserved in both types but kinetic energy conserved only in elastic collisions.
Key Concepts
- -- Work
- Work is the product of force and displacement in the direction of that force, expressed mathematically as W = F · d.
- -- Energy
- Energy is the capacity to do work, which exists in multiple forms such as kinetic energy (energy of motion) and potential energy (stored energy due to position).
- -- Power
- Power is the rate at which work is done or energy is transferred, calculated as the work done divided by the time taken, P = W/t.
- -- WorkEnergy Theorem
- The work-energy theorem states that the work done on an object is equal to the change in its kinetic energy, expressed as W = ΔK.
- -- Conservative Forces
- A conservative force is one for which the work done is independent of the path taken and depends only on the initial and final positions.
- -- Elastic vs. Inelastic Collisions
- In an elastic collision, both momentum and kinetic energy are conserved, whereas in inelastic collisions, momentum is conserved but kinetic energy is not.
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