Dynamics - Definitions Flashcards
Newton’s first law
A body will remain at rest or moving at a constant speed unless acted upon by an external force
Newton’s second law
The acceleration of an object is directly proportional to force and inversely proportional to the mass of the object
Newton’s third law
Every action has an equal and opposite reaction
Mass
The amount of substance or matter
Inertia
The property of matter that causes it to resist any change to its motion in either direction or speed
Weight
This is mass times gravity
Work
The amount of force required to cause movement
Power
The rate at which work is done
Force
What changes a body’s state of rest or of uniform motion in a straight line
Energy
The capacity to do work
Potential energy
Energy a body has by virtue of its position or condition, allowing it to do work when released
Kinetic energy
Energy a body has due its motion
Total energy
The sum of all different forms of energy in a system
Chemical energy
Energy which is stored in the chemical bonds between atoms
Thermal energy
The energy which a body possesses due to the kinetic energy and the potential energy of its molecules, also called internal energy
Heat energy
The flow of energy due to the difference in temperature between two bodies
Density
Weight per unit volume
Efficiency
The ratio of useful work out to total work put in
Momentum
A vector quantity that describes mass in motion
Elastic collision
Where things collide and just bounce with very little deformation occurring
Inelastic collision
A collision where two objects collide and stick together
Impulse
This is the product of a force and the time for which it acts
Rigidity
The tendency of a spinning gyro to remain fixed in space if it is not acted upon by outside forces
Friction
Force resisting the relative motion of an object, because of rubbing together
Starting friction/sliding friction
Friction present when a body that has been at rest begins to move, proportional to the weight of the body
Sliding friction
The friction present as a body slides over a surface, always less than starting friction
Rolling friction
The friction present between a rolling body and the surface on which it rolls, much smaller than sliding friction
Procession
If an external force is applied to change the direction, the gyro resists the change and moves at right angles to the direction originally applied
