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Definitions for Topic 2 - Mechanics: 2.1 - Motion 2.2 - Forces 2.3 - Work, energy and power 2.4 - Momentum and impulse
Newton’s first law
An object remains at rest or keeps moving at constant velocity unless an external force acts on it.
AKA. The law of inertia
Newton’s second law
The rate of change of momentum of an object is directly proportional to the resultant force applied and is in the direction of the resultant force
F=ma
Newton’s third law
Every action (action force) has an equal and opposite reaction (reaction force).
(The two forces have the same magnitude and point in opposite directions)
Translational equilibrium
When an object is either at rest or moving at constant velocity it is in translational equilibrium
The net force acting on an object is zero
Work
When a force acts on an object and as a result the object moves over a distance, the force has done work
Energy
The capacity for doing work
Can be transferred, when being transferred work is being done
Can not be created or destroyed
Kinetic energy
The energy that an object has because of motion
Ek=mv^2/2
Elastic potential energy
Energy stored as a result of applying a force to deform an elastic object
Ep=kx^2/2
Gravitational potential energy
The energy that an object has because of its position in a gravitational field
Ep=mgh
Power
The rate of doing work/amount of energy transferred or converted per unit of time
Momentum
The product of the mass and the velocity of an object
Principle of conservation of linear momentum
If no external force acts on a system, momentum remains constant
Impulse
The product of force and time
