1. Review for Test: velocity=(change in position)/time elapsed acceleration=change in velocity/time elapsed Meaning of force: Total force on an object F= Massx Acceleration Basic kinds of Force: gravitational and electromagnetic Kinetic energy of an object = (1/2)M v 2 Gravitational potential Energy= Mgh Energy is always conserved: Energy never disappears, though it can change type.

2. Thermal Energy Mechanical Energy Random atomic Coherent atomic motion or displacement Kinetic and potential energy energy Kinetic energy per molecule =1/2 Mv 2 measured by T Change in total Gravitational thermal energy= potential energy= massxspecific heatx Mgh temperature change

3. In the part of the course emphasized in test 2 we emphasized types of conversion of energy from one form to another: Mechanical Energy -> Thermal Energy Thermal Energy -> Thermal Energy (conduction, convection, radiation) Thermal Energy -> Mechanical energy Key points about these are reviewed in the next panels

4. Mechanical Energy -> Thermal Energy (Lab 4, HW 3, Ch 4B-C) Mechanical Energy is converted to Thermal energy by the performance of work done by frictional forces. Work is the amount of energy transferred = Fd where F is the part of the force acting along the direction in which it acts and d is the distance through which the force acts. If there is no freezing or boiling, the temperature rise is related to the thermal energy added by Thermal energy increase =massx(specific heat)x temperature increase

5. Thermal Energy -> Thermal Energy (Lab 5,6, HW4B,Ch 4D) Thermal energy change =massx(specific heat)x temperature increase Specific heat depends on the kind of material Energy is conserved in the transfer If there is boiling or melting then the thermal energy change (without change In temperature) is Mass converted from solid to liquid (in melting) or from liquid to gas (in boiling) X Latent heat of melting or vaporization

6. Thermal Energy -> Thermal Energy: Modes and Rates of energy transfer(HW4, Lab5, Ch5,6) Modes are Conduction, Convection and Radiation Rate of conduction= (Area x Temperature difference)/R = Area x( Temperature difference)k/thickness

7. Thermal Energy ->Mechanical energy (Lab 7Ch 4EF,Ch 7) Energy is conserved: Q H =W+Q C Conversion is never complete: Efficiency =W/Q H <1 Maximum efficiency=(1-T C /T H )