Energy

Created by

Ben Harper

Cards (18)

Energy is never created or destroyed, only transferred between different forms and objects
Different forms of energy include:
Thermal or internal energy (related to the heat energy trapped within an object)
Kinetic energy (associated with the movement or motion of an object)
Gravitational potential energy (energy an object possesses because of its position in a gravitational field)
Elastic potential energy (energy held in a stretched spring)
Chemical energy (held in chemical bonds)
Magnetic energy (holds magnets to surfaces)
Electrostatic energy (causes shocks when touching objects)
Nuclear energy (energy from breaking atoms apart)
Energy can be transferred between different energy stores mechanically, electrically, by heating, or by radiation
A system in physics refers to a collection of matter where energy can be transferred between objects or between different forms
In an open system, matter can exchange energy with the outside world, leading to energy loss or gain
In a closed system, neither matter nor energy can enter or leave, and the overall energy change is always zero
Examples of energy transfer:
Electrical energy from a plug socket to a kettle's heating element, then to the water's thermal energy store
Mechanical work done involves using a force to move an object, like kicking a ball
Electrical work is done when current flows, overcoming resistance in wires of a circuit
Work done is another way of saying energy transferred
Mechanical work involves using a force to move an object
Electrical work is done when current flows, overcoming resistance in wires
Friction does work by transferring energy from the wheel's kinetic energy store to the thermal energy stores of the surroundings, slowing down objects like a train
Kinetic energy is the energy that an object possesses due to its motion
Kinetic energy depends on two factors: speed and mass
The faster an object is moving, the more kinetic energy it will have
The more mass an object has, the more kinetic energy it will have, as long as speed is kept equal
In the equation, E represents energy, k represents kinetic energy, m represents mass in kilograms, and v represents velocity in meters per second
To calculate kinetic energy, ensure all values are in the correct units (e.g., convert tons to kilograms)
Example calculation for a plane:
Mass: 20,000 kg
Speed: 5 m/s
Kinetic energy = 250,000 joules or 250 kilojoules
Example calculation for a particle:
Mass: 0.0001 kg
Speed: 4000 m/s
Kinetic energy = 800 joules or 0.8 kilojoules
What is the equation to Kinetic Energy?
$Ke =$ $1/2 × mass × velocity^2$