Work, Energy, Power, Momentum Definitions Flashcards
Conservation of Energy
In a closed system with no external forces the total energy of the system before an event is equal to the total energy of the system after the event. The energy does not need to be in the same form after the event as it was before the event.
Efficiency
The useful output (e.g. power, energy) of a system divided by the total output.
Gravitational Potential Energy
The energy gained by an object when it is raised by a height in a gravitational field.
Kinetic Energy
The energy an object has due to its motion. It is the amount of energy that would be transferred from the object when it decelerates to rest.
Power
The work done or energy transferred by a system divided by the time taken for that to be done.
Work Done
The energy transferred when a force moves an object over a distance.
Conservation of Momentum
The total momentum of a system before an event must be equal to the total momentum of the system after the event, assuming no external forces act.
Elastic Collisions
A collision in which the total kinetic energy of the system before the collision is equal to the total kinetic energy of the system after the collision.
Impulse
The change of momentum of an object when a force acts on it. It is equal to the product of the force acting on the object and the length of time over which it acts
Inelastic Collisions
A collision in which the total kinetic energy of the system before the collision is not equal to the kinetic energy of the system after the collision.
Linear Momentum
The product of an object’s mass and linear velocity.
Newton’s First Law
An object will remain in its current state of motion, unless acted on by a resultant force. An object requires a resultant force to be able to accelerate.
Newton’s Second Law
The sum of the forces acting on an object is equal to the rate of change of momentum of the object.
Newton’s Third Law
Every action has an equal and opposite reaction. If an object exerts a force on another object, then the other object must exert a force back, that is opposite in direction and equal in magnitude.
