Calculate energy transferred by a force, then distinguish it from how quickly the transfer happens.
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Work is energy transferred when a force acts through a displacement. For a constant force parallel to the movement, W = F × d. A newton multiplied by a metre is a joule. Use metres, not centimetres, in that calculation.
Only the component of force along displacement contributes to work on that object. This lesson’s calculations use forces parallel to movement. A perpendicular force does no work through that displacement.
Power = work ÷ time. One watt means one joule transferred each second. Two motors can do the same useful work but have different power if they take different times.
Measure the force while moving at a steady speed, the displacement in the force direction, and the time. Repeated trials help reveal variation. Explain any assumptions instead of presenting a calculated value as a perfect measurement.
Change one measurement, predict the result, then compare the calculated account. These are editable teaching measurements, not a physical simulation.
Science North · Mechanism in action
Identify which force and displacement belong in W = F × d. Distinguish a steady lift from simply holding a heavy object.
A 40 N force moves a cart 3 m in 6 s, parallel to the movement. Find work and average power.
W = 40 × 3 = 120 J. P = 120 ÷ 6 = 20 W.
Describe one everyday situation that feels tiring but transfers no mechanical work to a stationary object.
Apply it to the design challenge →Read further: OpenStax · Simple Machines →
