CST 245 Exam Questions with correct Answers

Therodynamics - Answer- The study of energy transformations that occur in a collection of matter. Heat is transferred between two objects to reach equilibrium 3 systems: Open - capable of interacting with a surrounding environments and can exchange heat, work and matter outside their system Closed - can exchange heat and work, but not matter Isolated - can't exchange heat, work, matter to its surroundings. Boundary - refers to divisions between system and its surroundings Law of Thermodynamics - Answer- #0: Two objects in Thermodynamic equilibrium with a third object is also in equilibrium with each other (different objects at the same temperature) #1: Energy cannot be created nor destroyed. It can only be changed in form. #2: When energy changes, it is converted from a more useful more concentrated form to a less useful, less concentrated form #3: As temperature approaches absolute zero, entropy approaches a constant minimum. Also states that a system cannot be cooled to absolute zero Thermal contact - Answer- When heat flows from one object to another because they are in contact with each other Conduction - Answer- The direct transfer of heat from one substance to another substance that it is touching. Convection - Answer- Process by which, in a fluid being heated, the warmer part of the mass will rise and the cooler portions will sink. Radiation - Answer- Energy that is radiated or transmitted in the form of rays or waves or particles. heat energy (thermal energy) - Answer- The total kinetic energy of the particles that make up an object. The faster the particles move, the hotter an object becomes. measuring temperature - Answer- We measure temperature with degrees F, C or K. Celsius: 0 degrees - water freezes / 100 degrees boils Fahrenheit: 32 degrees - water freezes / 212 degrees - boils Kelvin is an absolute temperature scale: 273.15 - water freezes / 373.15 degrees - water boils Conversions of temperature - Answer- C to F: F (9/5)C + 32 F to C: (5/9)(f-32) C to K: C + 273.15 K to C: K - 273.15 heat capacity - Answer- the number of heat units needed to raise the temperature of a body by one degree. kinetic energy - Answer- energy of motion potential energy - Answer- stored energy that results from the position or shape of an object electromagnetic wave - Answer- type of energy contained in a field electrical energy - Answer- Energy caused by the movement of electrons. PE chemical energy - Answer- A form of potential energy that is stored in chemical bonds between atoms. solar energy - Answer- energy that comes from the sun sound energy - Answer- Energy caused by an object's vibrations Energy - Answer- The ability to do work or cause change mechanics - Answer- the study of the motion of objects Vectors - Answer- quantities that have both a magnitude and a direction Scalar - Answer- A physical quantity that has magnitude only. Motion - Answer- The state in which one object's distance from another is changing