Physics Homework 9.2.25 Flashcards
[Energy 4]
Define specific latent heat.
The energy needed to change the state of a system per kilogram (with no change in temperature)
Name two variables that affect the rate of cooling of a building through its walls.
Thickness and thermal conductivity.
Explain the difference between boiling and evaporation.
Boiling - Happens at the boiling point when the substance changes state.
Evaporation - Happens below the boiling point.
Name the store of energy associated with charged objects.
The electrostatic energy store.
State the effect on the temperature of a gas if the average kinetic energy of the particles increases.
The temperature increases.
Name the store of energy that the lubrication of moving parts with reduce energy transfers to.
Thermal energy store.
State the standard units for specific latent heat.
Joules per kilogram (J/kg)
Describe the cause of gas pressure.
The collisions of the gas particles with the walls of the container.
State the part of the internal energy that changes if the state of a system changes.
The potential energy of the particles.
Describe the relationship between internal energy, total kinetic energy of the particles and total potential energy of the particles.
Internal energy = total kinetic energy of the particles + total potential energy of the particles.
Define power.
The rate of energy transfer/ rate of work done.
State the term used to describe energy that is transferred to stores but is not useful.
Wasted energy.
Name the transfer of energy associated with forces changing the shape on an object.
Mechanical transfer.
State how unwanted energy transfers can be reduced.
Lubrication of thermal insulation.
In words, state the equation that links efficiency, total input energy transfer and useful output energy transfer.
efficiency = useful output energy transfer / total input energy transfer.
State the law of conservation of energy.
Energy cannot be created nor destroyed, only transferred between stores.
State the part of the internal energy that changes if the temperature of an object changes.
The total kinetic energy of the particles.
Describe the relationship between the thermal conductivity of a building’s walls and the rate of energy loss from the building.
As the thermal conductivity of the walls increases, the rate of energy loss decreases.
State the standard units for power.
Watts (W)
Name the method that should be used to measure the volume of an irregularly shaped object.
Displacement method.
