Work, Energy and Power: notes and previous year questions

Free notes for every topic in work, energy and power, with the key formulas and real JEE and NEET questions solved step by step.

Work Done by ForcesWhat work means in physics, W = F s cos θ, work with vectors, its sign, work by a changing force, and work by gravity, springs, friction and the normal force.
Kinetic EnergyKE = ½mv² and where it comes from, why speed enters squared, the link KE = p²/2m, and kinetic energy in spinning and rolling bodies.
Work-Energy TheoremThe net work of all forces equals the change in kinetic energy: when to use it, and the one-line patterns for stopping, bullets, springs, falls and rough slopes.
Potential EnergyEnergy stored by position or shape: mgh, ½kx², W = −ΔU, F = −dU/dx, equilibrium, and reading a U–x graph.
Conservation of Mechanical EnergyKE + PE stays constant when only conservative forces do work: falls, slides, pendulums, springs, pulleys, and what changes when friction acts.
Vertical Circular MotionSpeed and tension around an upright circle, the critical speeds √(gr) and √(5gr), the 6mg rule, slack strings, rods, loop tracks and humps.
PowerThe rate of doing work: P = W/t and P = F · v, units and the kilowatt hour, lifting, top speed, constant power, and power–time graphs.
CollisionsMomentum always, kinetic energy sometimes: restitution, elastic and sticking collisions, the energy lost, any e, and collisions in two dimensions.