Physics · Work, Energy & Power
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Hard Problems
20 exam-style word problems · Multiple choice · Instant explanations
⚡ Quick-Fire Memory Points
Work
W = Fd·cosθ
force × displacement × cosine of angle
Kinetic Energy
KE = ½mv²
faster = WAY more energy (squared!)
Gravitational PE
PE = mgh
height gained = energy stored
Conservation
KE₁+PE₁ = KE₂+PE₂
no friction → total stays same
Work-Energy Thm
W_net = ΔKE
net work changes kinetic energy
Power
P = W/t = Fv
energy per second = watts
Friction Work
W_f = −μₖmg·cosθ·d
negative sign = energy removed
Centripetal
F_c = mv²/r
directed inward, always