Head to to save 10% off your first purchase of a website or domain using code FLOATHEADPHYSICS In this video, we rediscover Einstein's equivalence principle. It solves one of the biggest mysteries of Newtonian physics - why gravitational mass = inertial mass. But in doing so, Einstein completely reinvents the ideas of gravity. Starting with gravity being an illusion. A mere side effect of the 'ground' accelerating 'upwards'. Basket Ball Feather Video Hammer Feather Video This video is sponsored by squarespace