YuzheJun 11, 2017Charging by Contact and by Induction - physics/物理(a) When a charged rod is brought near the metal sphere without touching it, some of the positive and negative charges in the sphere are...
YuzheJun 11, 2017Law of Conservation of Electric Charge - physics/物理Like charges repel and unlike charges attract each other. A new technology based on the electric force may revolutionise the way books...
YuzheJun 7, 2017The Principle of Conservation of Mechanical Energy Mechanical Energy - physics/物理The total mechanical energy (E = KE + PE) of an object remains constant as the object moves, provided that the net work done by external...
YuzheJun 7, 2017Apparent weight - physics/物理A person whose true weight is 700 N steps on the scale. If the elevator is at rest or moving with a constant velocity (either upward or...