power and electrical power
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13 November 2014. Power and electrical power. Keywords : Power, Energy, Weight, Force. Outcomes. All students should be able to describe what makes an object powerful or not. Most students should be able to define power and use the equation. - PowerPoint PPT PresentationTRANSCRIPT
Power and electrical power
19 April 2023
Keywords: Power, Energy, Weight, Force
ObjectivesUnderstand what power is and be able to calculate it.
HSW: AF5 – Working critically with evidence AF4 – Using investigative approaches
Used before in: lesson 1 – work Will use again in:
PLTS: Team workers – Work collaboratively with others.
Used before in: Science A Will use again in:
Outcomes
• All students should be able to describe what makes an object powerful or not.
• Most students should be able to define power and use the equation.
• Some students should be able to evaluate practical work and describe how to make it more valid and reliable.
Powerful cranes
Which is the most powerful crane? Explain why.
How is power calculated?The power exerted by an object can be calculated using one of two equations:
Time is measured in seconds (s).
Power is measured in watts (W).
Work done is measured in joules (J).
work done
time takenpower =
Remember that work done = energy transferred.
A lawnmower engine does 10
kJ of work in 10 seconds. What is the power of the engine?
Calculating power question 1
= 1,000 W = 1 kW
power =work done
time
= 10,000 / 10
A car transfers 12 mJ of energy in 2 minutes. What is the power of the car?
Calculating power question 2
= 100,000 W = 100 kW
= 12,000,000 / 120
power =work done
time =energy transfer
time
Power, work and time calculations
Anagrams
And finally – we find out – who are more powerful – boys or girls?
• Force x distance = energy• Energy/time = power
Boys: Girls:
Force Dist for 1 rep
reps Total dist
work time power Force Dist for 1 rep
reps Total dist
work time power
Skipping
Lifting
Push ups
Analysis: What conclusion can you draw? Evaluation: was the evidence reliable? Explain.
Energy Gravitational Watts
Heat Power Kinetic
Electrical1 Joule per
secondJoules
Plenary - Multiple-choice quiz