Physics Essay Summary Example For Students

Physics Essay Summary Strictly speaking, will a penny be slightly more massive if it has a negative charge or a positive charge? Explain. A negative charge because when it is negatively charged electrons are added to the penny. 17. What is the voltage at the location of a 0. 0001 C charge that has an electric potential energy of 0. 5 J (both voltage and potential relative to the same reference point)? Potential = energy Charge = 0. 5 J / 0. 0001 c = 5,000 v 20. Why? Brass doesnt erode and it doesnt polarize. Next the reason it is recorded on a metal plaque is to show record of where the boat was manufactured and to give a changeless frame number and year it was constructed or dispatched. 34. Your friend says that, if you crank the shaft of a DC motor manually, the motor becomes a DC generator. Do you agree or disagree? Defend your position. Agree. Any coil of wire spinning in a magnetic field that cuts through the magnetic field is a generator. 41 . How does the current in the secondary of a transformer compare with the current in the primary when the secondary voltage is twice the primary voltage? Transformers must conserve energy. Since the energy of an electric current is proportional to the product of current and voltage and since energy output must be equal to or less than the energy input, increasing the voltage requires a responding decrease in current! If voltage increases by lox then the current must usually is, less. ] 48. What is wrong with the following scheme? To generate electricity without fuel, arrange a motor to run a generator that will produce electricity that is stepped up with transformers so that the generator can run the motor and simultaneously furnish electricity for other uses. Every step described in this process involves some form energy dissipation in the form, usually in the form of heat. All this can do is to waste energy. The motor heats up, the transformer heats up and the generator heats up.