Topic Sheet 9.2 Flashcards
What is the principle of energy conservation?
The total energy in a closed system remains constant during energy transfers.
What does a Sankey diagram represent?
It visually represents energy transfers within a system.
What is the formula for calculating change in gravitational potential energy?
ΔGPE = m x g x Δh
What factors affect the change in gravitational potential energy?
- Mass (kg) * Gravitational field strength (N/kg) * Change in vertical height (m)
What is the formula for kinetic energy?
KE = ½ x m x v²
What factors determine kinetic energy?
- Mass (kg) * Speed (m/s)
Define power in the context of energy transfer.
Power is the rate at which energy is transferred.
What is the equation for power?
P = E/T
What does one watt equal in terms of energy transfer?
One watt is equal to one joule per second.
List the different types of energy stores.
- Chemical energy * Kinetic energy * Thermal energy * Strain energy * Elastic potential energy * Gravitational potential energy * Atomic energy * Nuclear energy * Light * Electricity
What are the common ways through which energy can be changed in a system?
- Work done by forces * Electrical equipment * Heating
What occurs during energy dissipation in a system change?
Energy is stored in less useful ways.
How can efficiency be increased?
By reducing unwanted energy transfers.
What is the equation for efficiency?
Efficiency = (useful energy transferred) / (total energy supplied)
What happens to mechanical processes that cause a rise in temperature?
They become wasteful by dissipating energy as heat.
What are some methods to reduce unwanted energy transfer?
- Lubrication * Thermal insulation
What qualitative effects do wall thickness and thermal conductivity have?
They affect the rate of cooling of a building.
Fill in the blank: The change in gravitational potential energy is measured in _______.
joules
True or False: Energy transfers in a closed system result in a net loss of energy.
False
