P1-Physics- Energy

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  • Created by: DonaJ2002
  • Created on: 30-01-18 21:07

P1- Energy

Energy Stores and Systems

Conservation of Energy= stored,transferred or disspiated but cannot be created or destroyed

When energy is transferred to an object, the energy is stored in one of the object's energy stores such as: (Most Kids Hate Learning GCSE Energy Names)

1) Magnetic

2) Kinetic

3) Heat (Thermal)

4) Light

5) Gravitational potential

6) Chemical

7) Sound

8) Elastic

9) Electricity 

10) Nuclear

Energy is transferred Mechanically (by a Force doing Work), Electrically (Work done by Moving charges), by Heating or by Radiation.

When a system (object) changes, Energy is transferred. It can be Transferred Into or Away from the system, between dfferent objects in the system or between different types of energy stores.

Closed Systems= neither Matter or Energy can Enter or Leave. Net change in total energy of a Closed system= 0

Efficiency= Output/ total Input

Kinetic Energy store= Movement of an object

Energy Transferred TO object= High Kinetic (Speeds up)

Energy Transferred AWAY from objec= Low Kinetic (Slow)

Greater Mass= High Kinetic (Faster)+ More Energy in Store

Kinetic= 1/2 x Mass x 2Velocity

(J)              (kg)        (m/s2)

Gravitational Potential Energy Stores= Raised Objects

The higher the object is lifted= More energy stored in store

Higher Mass= More energy stored in GPE store

Higher GFS= More energy stored in GPE store

GPE (Ep)= Mass x GFS x Height

(J)    (kg)   (N/kg)  (m)

Falling objects transferred from GPE to Kinetic. For a falling object without air reistence: Engergy Lost from GPE= Energy Gained form Kinetic.

Elastic Potential Energy= Stretching/ Squashing

As long as the limit of proportionality has not been exceeded, energy in the Elatic potention of a stretched spring can be found using:

ELastic (Ee)= 1/2 x Spring Constant(K) x Extension2 (e2)

Specific Heat Capacity= Amount of energy needed to raisethe temperature of an object. Formula for Change in Thermal Energy= Specific Heat x Mass x Change in Temp.

       (J)            (J/kgC)       (kg)          (C)

*PRACTICAL- Investigating Specific Heat Capacities

Conservation of Energy Principle

Energy can be Transferred usefully, Stored or Dissipated (Wasted) but CANNOT be Created or Destroyed.

When energy is Transferred Not ALL energy is transferred USEFULLY into stores- Some are Dissipated (Wasted) usually Thermal.

E.g. Mobile= System. -> Energy Usefully Transferred into Chemical Energy of Battery; Some energy Dissipated as Thermal after a while of usage.

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