Introductory Mechanics Flashcards
(22 cards)
Speed
The distance moved by a body per unit time
Velocity
The change in a body’s displacement per unit time
- Velocity tells us how quickly the position is changing
Acceleration
The time rate change in a body’s velocity
- Acceleration tells us how quickly the velocity is changing
Acceleration may result from:
- A change in the bodies speed
- A change in the bodies direction
- A change in both speed and direction
Negative Acceleration
A body undergoes negative acceleration if it’s velocity decreases with time.
Newton’s 1st Law of Motion
A body will remain at rest or continue in its state of uniform motion unless acted upon by a net external force
- A body at rest under Newton I has balanced forces acting on the same body
Inertia
The tendency of a body to remain at rest or continue with constant velocity
- Mass is a measure of the inertia of a body
- Greater mass = Greater inertia
Momentum
The product of a body’s mass and its velocity
Change in Momentum
The vector difference between the bodies’ final and initial momenta
Newton’s 2nd Law
When a net external force is applied to a body it produces a change in the body’s momentum
- Rate of change in momentum of a body is directly proportional to the applied net force
Weight
The gravitational force exerted on it by the Earth or other massive body
- Weight is a force due to gravity
Tension in Strings
The tension in a string is the force that the string applies to the body to which it is connected
Newton’s 3rd Law
To every action there is an equal and opposite reaction
- Forces always act in pairs
- The two forces act on different bodies thus they do not cancel each other out
Normal Reaction Force
When a body is in contact with any surface, that surface exerts a force on the body and this force acts perpendicularly to and away from the surface
- A surface is said to be ‘smooth’ if the normal force is the only force which the surface exerts on a body moving across it
Impulse
The product of a force and the time for which it acts
Conservation of Linear Momentum
When two or more bodies interact the sum of their momenta before interaction is equal to the sum after interaction
- The total momentum of a closed system will remain constant
Work
Work is done when the point of application of a force is moved in the direction of the force
Energy
The capacity of a body to do work
Kinetic Energy
The energy possessed by a body due to its motion
Potential Energy
The energy of a body due to its position or state
Gravitational Potential Energy
When a body is lifted up to a level above the Earth’s surface, its potential energy increases as a result of its change in position relative to the Earth
Conservation of Energy
Energy can neither be created nor destroyed
- The total energy content of a system (Et) remains constant
- Energy may be transformed from one form to another
Power
The amount of work done per unit time
