p7.1 Flashcards
What is energy?
Energy is a quantity (a number in joules) that indicates what is possible, but does not determine outcomes.
What is an energy store?
An energy store is a concept used to indicate the amount of energy in joules associated with different types of energy.
What does the Law of Conservation of Energy state?
Energy cannot be created or destroyed; it can only be transferred between stores.
What happens to gravitational energy when a skier goes down a hill?
The energy in the gravitational store decreases.
Name three types of energy stores.
- Chemical
- Thermal
- Kinetic
What is the equation related to thermal energy?
change in thermal energy = m x specific heat capacity x change in temperature.
How is energy transferred mechanically?
Energy is transferred mechanically by applying forces.
What is the formula for work done?
work done = force x distance.
What is the formula for energy transferred electrically?
energy transferred = electrical power x time.
What type of energy store is represented by a moving car?
Kinetic energy store.
Fill in the blank: Energy is not a substance, like a liquid or a fuel, or a _______.
[process]
What happens in a closed system regarding energy?
There is no net change in energy; energy is conserved.
True or False: Energy can be created in a closed system.
False.
What analogy is often used to explain energy?
Energy is likened to money, as both are conserved.
Provide an example of an energy store decreasing.
- A cup of tea cooling down
- A woman on a bungee cord getting shorter
- Wood burning on a fire
What type of energy transfer occurs when stretching an elastic band?
Mechanical energy transfer.
Why is the water warmer at the bottom of a waterfall?
Due to gravitational potential energy being converted into thermal energy.
What is the equation related to gravitational energy?
E = mgh, where E is energy, m is mass, and g is gravitational field strength.
What is the equation for elastic energy?
E = 1/2 kx^2, where k is the spring constant and x is the extension.
What is the relationship between energy and temperature in a thermal store?
As thermal energy increases, temperature also increases.
What do we mean by ‘thermal energy’?
It is shorthand for energy in a thermal store.
what energy store is fuel?
chemical
