Topic 2.3: Work, Energy, and Power Flashcards Preview

IB SL Physics > Topic 2.3: Work, Energy, and Power > Flashcards

Flashcards in Topic 2.3: Work, Energy, and Power Deck (12)
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• 2.3.1: Outline what is meant by work

o WORK: Work is done when a force moves an object in the direction of the force. Work is a scalar quantity


Define joule

o JOULE: The unit of energy. The SI unit is the joule. 1J=1N*1m


• 2.3.2: Determine the work done by a non-constant force by interpreting a force-displacement graph

o WORK DONE BY A NON-CONSTANT FORCE: Work done is the area under the force-distance graph. Eg for Hooke’s law, W=½kx^2


Define energy

o ENERGY: The ability to do work.


• 2.3.4: Outline what is meant by kinetic energy

o KINETIC ENERGY: Energy an object has as a result of its motion.


• 2.3.5: Outline what is meant by change in gravitational potential energy

o GRAVITATIONAL POTENTIAL ENERGY: Energy an object has a result of its position in a gravitational field.


• 2.3.6: State the principle of conservation of energy

o PRINCIPLE OF CONSERVATION OF ENERGY: Energy is never created nor destroyed. It just changes from one form to another.


Define elastic collisions

o ELASTIC COLLISIONS: KE is conserved in these collisions. (Momentum is conserved in every collision).


Define explosive collisions

o EXPLOSIVE COLLISIONS: KE is increased in this collision


Define inelastic collisions

o INELASTIC COLLISIONS: The total KE is decreased. If the objects stick together, the collision is PERFECTLY inelastic.


Define power

o POWER: The rate of doing work. Unit is the watt. 1W=1Js-1


• 2.3.10: Define and apply the concept of efficiency

EFFICIENCY: Fraction of energy which is usefully transferred.
Efficiency=(useful work done)/(total work done)