6.1.1 Energy Stores and Systems Flashcards
What is a system?
an object or a group of objects.
What happens when a system changes?
The way energy is stored will change.
What are the eight types of energy store?
Chemical Gravitational Elastic Nuclear Electrostatic Magnetic Kinetic Thermal
What are the energy transfers in when a ball is thrown up in the air and reaches its highest point?
Chemical in a human;
becomes kinetic in the ball;
which turns to gravitational in the ball as it gets higher
What is needed for a complete description of a system?
The object or groups of objects
The type of energy being stored
What is needed when talking about a change in a system?
A starting point and a end point.
What are the energy transfers in when a pen is dropped in the desk?
gravitational in the pen;
becomes kinetic in the pen as it falls;
which becomes thermal in the pen and surroundings
What are the energy transfers in when a wind up toy is released?
Elastic energy in the spring;
becomes kinetic energy in the toy
What is meant by the term conservation of energy?
Energy cannot be created or destroyed;
only transferred between systems and stores.
What is energy measured in?
Joules (J)
If 120 joules of energy input in to a system, how many joules will be output?
The same number. 120 joules
What do we often call energy that has been dissipated in a less useful way?
It has been wasted.
What is the equation relating work done, force and distance?
work done = force x distance moved in the direction of the force.
What is the unit of force?
Newtons (N)
What is the unit of distance?
Metres (m)
What happens when a force causes an object to move a distance?
Work is done;
energy is transferred.
What is the relationship between work done and energy transferred?
Work done = energy transferred.
How do we define 1 joule?
1 joule of work is done when a force of 1 N causes a displacement of 1 m.
What happens when work is done against friction?
A object or system gains energy in the thermal store;
the object gets hotter/its temperature increases.
What is the equation relating gravitational energy, height, mass and g?
Gravitational energy = mass x g x height
GE = mgh
When an object is dropped, what happens to the amount of gravitational energy it has?
The gravitational energy decreases;
as the change in height is negative
What is the unit of mass?
Kilograms (kg)
When dealing with mass, which unit should we use?
Kilograms (kg)
What is the unit of height?
Metres (m)
