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Charge & Coulomb’s Law A. Charge 1. is the source of the _________________ ______________ 2. can neither be _____________ nor _____________ only ______________________ 3. has the SI units of _________________________ 4. is _____________________ in units of _________________ 5. comes in only __________ ___________ which are called ___________ and ____________. 6. Like charges __________ and unlike charges ____________ B. Terminology 1. Neutral body is a body with ___________ amounts of ________ and __________ charge. 2. __________________ is a material in which charge is free to flow. Type 1: Type 2: 3. ________________ is a material in which charges are not free to move. 4. _______________ are materials between insulators and conductors in the difficulty for charges to move. C. 1. Two Ways to Charge a Body _____________ is the transfering of ______________ between two bodies due to ________________ between the bodies. 2. __________________ is the influencing of _____________ on a body due to a _______________ ____________ that is nearby but _________ ______________ the 1st body. D. Electric Force and Gravity Definitions: Electric force is the force between two bodies due to charge on the bodies - Gravitational force is the force between two bodies due to the mass of the bodies 1. Universal Law of Gravity (point/spherical masses) 2. Coulomb’s Law (point/spherical charges) These two formulas are important because more complicated problems can be broken down into collections of point masses/charges and the forces summed using superposition. 3. Comparison Properties Source Type Range Strength Electric Gravity Mass Attractive ∞ Weak Problem 1: Three charges are situated as shown below. Find the net force upon the 1.0 nC charge. 2.0 C 0.5 m 1.0 nC 0.5 m 2.0 C 1.0 m Solution: Physics - Given: 1. Draw a Free Body Diagram 2. Find Magnitude of Each Force Equations: 3. Find the Components of the Forces 4. Add vectors by adding vector addition 5. Draw the Resultant Vector Force 6. Find the magnitude and angle of resultant using the vector force diagram. Problem 15.5 in Serway/Faughn The nucleus of 8Be, which consists of 4 protons and 4 neutrons, is very unstable and spontaneously breaks into two alpha particles (helium nuclei, each consisting of 2 protons and 2 neutrons). (a) What is the force between the two alpha particles when they are 5.00x10-15m apart, and (b) what will be the magnitude of the acceleration of the alpha particles due to this force? Note the mass of an alpha particle is 4.0026u. Note: 1.007276 u = 1.67265x10-27 kg (Back of textbook) Figure: Physics: Given: Soultion: Equations: