Ключевые слова: background, backlit, bend, blurred, cause and effect, close up, closeup, coil, coil spring, compress, compression, concept, dynamic, dynamics, elongationcompression, energy, energy flexibility, equal and opposite, example, experiment, expression, finger, force, gone, hand, handoperated, holding, isolated, jump, lose, metal, physics, physics class, pinch, potential, power, pressure, push, quantity, reaction, recoil, release, science, shoot, speed, spiral, spring, tension, thumb, twist,