Work, Power & Energy
Understanding energy, work-energy theorem, and conservation of mechanical energy.
Types of Mechanical Energy
⚡ Kinetic Energy
Energy of motion. Depends on mass and speed.
KE = ½mv²
🌍 Gravitational PE
Stored energy due to height above reference.
PE = mgh
🔧 Spring PE
Stored energy in a compressed/stretched spring.
PE = ½kx²
🔋 Total Energy
Sum of KE and PE. Conserved in ideal systems.
E = KE + PE
Work & Work-Energy Theorem
Work is done when a force causes displacement in the direction of the force.
Work Formula
W = F·d·cos θ
θ = angle between force and displacement
Work-Energy Theorem
W_net = ΔKE = KE_f − KE_i
Net work equals change in kinetic energy
Conservation of Energy
In the absence of friction and air resistance, total mechanical energy is constant.
KE₁ + PE₁ = KE₂ + PE₂
½mv₁² + mgh₁ = ½mv₂² + mgh₂
🎯 Free-fall example
At the top: all PE. At the bottom: all KE.
v = √(2gh)