Physics 100 - Final Exam Questions With Verified Correct Complete Solutions.

How is a scalar quantity different from a vector quantity? Give examples of each. - correct answer Scalar: quantity measured in just magnitude. Example is speed - how fast something is going. Vector: quantity measured in both magnitude and direction. Example is velocity - My bike is going 9.8 ft/s west. State Newton's three laws of motion. - correct answer 1. Object at rest or in motion stays unless outside force 2. F=MA - (force = mass x acceleration) 3. For every action there is an equal and opposite reaction A bowling ball and a baseball are dropped at the same time from the same height. Which has the larger mass? As they fall, which has the larger force due to gravity? Ignoring air friction, which has the larger acceleration? Explain. - correct answer The bowling ball has the larger mass. The bowling ball has the larger force due to gravity. Both the bowling ball and the baseball have the same acceleration because the rate of acceleration is the same for all objects. Distinguish between momentum and impulse. What does it mean to say that momentum is conserved? - correct answer Momentum is mass multiplied by velocity and Impulse is how long a force is applied for. Momentum of a system stays the same but can transfer from one object to another. What is work, and what is energy? What does it mean to say that energy is conserved? - correct answer Work: when you exert a force on an object and it causes that object to move a certain distance. Energy: the ability to do work, cause change, or produce heat. Energy cannot be created nor destroyed but can be lost due to heat. What is the difference between centripetal and centrifugal force? - correct answer Centripetal force pulls objects inward, whereas, centrifugal force pushes objects outward Distinguish between momentum and angular momentum. What does it mean to say that angular momentum is conserved? - correct answer Momentum = when mass is multiplied by velocity, the answer is a measure of Momentum. Angular momentum= the product of a rotating object's moment of inertia and its angular velocity is the Angular Momentum of the object. Conservation of Angular Momentum = the Law of Angular Momentum states that the momentum of any closed, isolated system does not change. If the force due to gravity diminishes as we get farther from Earth, why do we say that the acceleration due to gravity is constant near the Earth's surface? - correct answer Because of acceleration due to earth's gravity is 9.8 m/s. Why are satellites put in orbit so high above the Earth's surface? - correct answer So that they are above Earth's atmosphere Consider the isotope of aluminum, 2713Al. How many protons are there? How many neutrons are there? How many electrons are there (if the atom is neutral)? How many electrons are in each shell? Explain your answers. - correct answer 13 protons 14 neutrons 13 electrons Electrons in each shell 1st shell = 2 2nd shell = 8 3rd shell = 3 What are the three phases of normal matter? What factor(s) will determine the phase? - correct answer Solid, Liquid and gas. Temperature and Pressure determine its phase. What is the difference between internal energy, heat, and temperature? - correct answer Internal energy = of a system is the total potential and kinetic energy of the system. Heat = is thermal energy transferred to body from hot to cold. Temperature = is directly proportional to the amount of kinetic energy the individual particles have within a body. What are the three ways to transfer heat energy? Explain each. - correct answer Conduction = the transfer of heat energy by molecular and electron collisions with a substance (especially a solid). Convection = the transfer of heat energy in a gas or a liquid by means of currents in the heated fluid. Radiation = the transfer of energy by means of electromagnetic waves Why do solid objects expand when heated? - correct answer Objects expand when heated because the heat 'gives' molecules more energy, so they move around more. This vibration, as molecules are pushed further apart, is manifested as a larger volume. What are the three (actually four) laws of thermodynamics? - correct answer 0. Heat will never flow between two bodies of identical temperature 1. Energy is neither created nor destroyed 2. Useful energy in a closed system always declines (entropy always increases) 3. Energy can approach but never attain absolute zero (would require heat transfer with a body somewhere colder than absolute zero = impossible) What is a heat engine? What is known about the efficiency of an ideal heat engine? - correct answer A heat engine takes in energy as heat and uses a portion of it to do work. The bigger the temperature difference is, the greater the ideal efficiency. Distinguish between an electric force and an electric field. Distinguish between electric potential energy and electric potential. - correct answer Electric Force = When two charged objects interact, they exert an electric force on each other Electric Filed = a "force" field around a charged object Electric Potential Energy = the potential energy of an electric charge Electric potential = at a point is the amount of work done in bringing a unit positive charge from infinity to that point.