There are two types of charges - positive and negative. When similar charges come near each other they are attracted. When opposite charges come near each other they are repelled. Conductors allow charges to pass through them while insulating materials don't allow charges to pass through them. Charges can neither be created nor destroyed. When opposite charges come in contact with one another they neutralise each other. ---- There are two types of charges - positive and negative. When opposite charges come near each other they are attracted. When similar charges come near each other they are repelled. Conductors allow charges to pass through them while insulating materials don't allow charges to pass through them. Charges can neither be created nor destroyed. When opposite charges come in contact with one another they neutralise each other. ---- There are two types of charges - positive and negative. When opposite charges come near each other they are attracted. When similar charges come near each other they are repelled. Conductors allow charges to pass through them while insulating materials don't allow charges to pass through them. Charges can neither be created nor destroyed. When opposite charges come in contact with one another they neutralise each other. There is another concept called grounding that we need to know. Grounding is like a big neutral sink where charges can flow. The earth is like grounding. When a charged object is connected to grounding then the charges will flow to it and it will become neutralised. ---- When an object is moving at constant speed force is zero. When calculating work done by a force we only consider the component of force in the direction of displacement. Kinetic energy is the energy of an object while it is in motion that is it has a velocity. Potential energy is a form of energy that an object has due to it's position with respect to gravity. Work done is the net change in energy of an object. Total energy of a system is conserved when there are no external forces, i.e., it can neither be created nor be destroyed, only transferred. -----