Power | Physics for GCSE/IGCSE - Year 11 PDF Download

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Power

• Machines like car engines continually shift energy from one energy store to another throughout a duration.
• The pace of this energy transfer, termed power, denotes the rate of work done.
• Time plays a crucial role in understanding power.
• When two cars expend an identical amount of energy or perform the same amount of work to accelerate over a distance, the one with higher power accomplishes this task in a shorter timeframe.

• Two electric motors raise an identical weight by the same height, yet one motor lifts it more rapidly than the other.
• The motor that elevates the weight at a faster pace possesses greater power.

• Appliances are assigned power ratings to indicate the energy transferred per unit time.
• Common power ratings are detailed in the table below:

Calculating Power

• Since power is defined as:
  The rate of doing work
• And work is:
  Work done = energy transferred
• Then, power can be expressed in equation form as:
  
• In the equations:
  • W or ΔE represents the work done or energy transferred, measured in joules (J).
  • t denotes time, measured in seconds (s).
  • P signifies power, measured in watts (W).
• It's important to note that although these equations may be expressed differently, they convey the same concept - the transfer of energy over time.
• The rearrangement of this equation can be facilitated with the assistance of a formula triangle.