Work & Energy
Year 9 🚀 Forces & Motion Calculate work done: W = Fd; link to kinetic and potential energy.
💪 Work Done
Work is done when a force moves an object. Work is measured in Joules (J).
Work Done
$$W = Fd$$
$W$ = work done (J) · $F$ = force (N) · $d$ = distance in direction of force (m)
If the force is perpendicular to motion, no work is done (e.g. carrying a bag horizontally).
⚡ Kinetic & Potential Energy
Moving objects have kinetic energy. Objects at a height have gravitational potential energy.
KE and GPE
$$KE = \frac{1}{2}mv^2 \qquad GPE = mgh$$Falling object: As it falls, GPE converts to KE. At the bottom: ½mv² = mgh (ignoring air resistance)
♻️ Conservation of Energy
Energy is never created or destroyed — it is only transferred between stores.
Pendulum: At the top → all GPE. At the bottom → all KE. In between → mixture of both.
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⚡ Work & Energy Calculator
Work Done
KE & GPE