Experiments you can run yourself.
Horizontal projectile motion: why objects fall in the same time regardless of horizontal speed. Interactive simulation, formulas for range and fall time, step-by-step explanation.
Conservation of momentum: total momentum before equals total momentum after a collision. An interactive simulation of elastic and inelastic collisions, with the formulas and a kinetic-energy balance.
The law of conservation of mechanical energy: how potential energy turns into kinetic energy. An interactive roller coaster, with the formulas Ep = mgh and Ek = ½mv².
Newton's second law of motion: how force and mass determine acceleration. An interactive motion simulation, the formula F = ma and a = F/m.
Hooke's law: why a spring's extension is proportional to the applied force. Interactive simulation, the formula F = kx, the spring constant and the elastic limit.
Circular motion and the centripetal force: why it grows with the square of the speed. An interactive simulation, the formula F = mv²/r, and what happens when the constraint is cut.
Newton's first law of motion: a body with no net force keeps its state of rest or uniform motion. Interactive simulation of inertia and the role of friction.
Newton's third law: action and reaction forces are equal and opposite, and act on two different bodies. An interactive recoil simulation.