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Mechanics Concepts (v17)

Page history last edited by Bob-RJ Burkhart 7 years, 7 months ago


 Visual Taxonomy

Taxonomy Path





L1 Mechanics Concepts
Level 2 University

change in speed over time, whether speeding up or slowing down

Change in velocity (not speed!) over time  

Air Resistance

friction acting on an object moving through air

Average Speed

the total distance traveled divided by the time required to travel that distance


Balanced Forces

when two forces combine to cancel each other out

Centripetal Acceleration
  Acceleration acting on an object moving around a circle and directed toward the centre of the movement.  
Centripetal Force   Force acting on an object moving around a circle at constant speed (but at the direction of movement changed)  
Change in Momentum in One Dimension   Momentum is changed under the influence of a force acting along the movement of an object, in the same or opposite direction  
Circular Motion   Movement around a circle (at constant speed with one force only providing centripetal force)  
Conservation of energy

(energy) cannot be created or destroyed

The total energy before the work is done equals the total of all the forms of energy produced afterwards.  
Conservation of Momentum in One Direction   Total momentum of two or more objects before and after collision (explosion) is the same / equals.  

Constant Speed

speed is not increasing or decreasing but remain consistent over time

Constant unchanging    

Contact Area

amount of area shared by two objects e.g. ice skates have sharp edges, and thus a small area in contact with the ice


decrease in the speed over time of an object

Displacement   Distance in vector form, when direction of movement is important  

how far an object has traveled (usually horizontal)



or an object moving through air, friction is called "air resistance" or "drag



kinetic energy; the kind of energy possessed by moving objects



gravitational potential energy; energy possessed by objects that have been lifted up

Elastic Collision   Collision involving no loss of kinetic energy due to no change in shape of objects.  
Elastic Potential Energy   Energy stored in an extended or compressed spring  
Energy Gained Energy accumulated at Energy Transfer, e.g. transfer of Kinetic Energy to Potential Energy at ROPE CLIMBING    
Energy Loss Energy scattered on friction or Air Resistance at Energy Transfer    
Energy Transfer Transformation between different kinds of energy    

State of an object at rest or moving uniformly.

Condition: both the resultant force is zero and the sum of all the torques acting on a object is zero.

Final Velocity   Velocity at the end of movement (considered / measured)  

a push or pull that can change an object’s movement

Force Components   Projections of force on selected directions  

Free Fall

falling motion caused by gravity alone


friction is an opposing force; it acts in the opposite direction to a force which is applied to an object


acceleration caused by the earth’s mass (approx. 10 ms-2)


slope of a graph (rise/run)

Gravitational Potential Energy   Change of position of an object in the Earth's gravitational field.  

the force of attraction between any two objects; the Earth is very big and so has a large gravity pulling everything down towards it


distance (vertical)

Impulse   Change of Momentum under the influence of force F acting over the period of time Δt.  
Inelastic Collision   Collision involving loss of kinetic energy due to change in shape and/or temperature of objects.  
Initial Velocity   Velocity at the beginning of movement (considered / measured)  


at an instant of time

Instantaneous Speed

speed at a particular instant in time

Kinetic Energy   Energy of a moving object  

amount of matter in an object or substance


Mechanical Energy

kinetic or potential (or heat) energy

Momentum (p)   "quantity of motion" proportional to the velocity and mass of an object  

Net Force

the single force that represents all the forces acting on a body; overall force


Power (P), W

the rate that energy is changed from one type to another;

power is the energy changed divided by the time it takes for the energy to change

The rate at which work is done  

a measure of the force exerted on a certain area of surface; force per unit area

Projectile Motion   Motion of a projectile, an object moving through the air without its own source of power, only under the influence of gravity  

An equal and opposite force exerted by a body against a force acting upon it


information that can be used to link two things together e.g. force and acceleration


Resultant Force

a stationary object remains stationary if the sum of the forces acting upon it - resultant force - is zero. A moving object with a zero resultant force keeps moving at the same speed and in the same direction. If the resultant force acting on an object is not zero, a stationary object begins to accelerate in the same direction as the resultant force.


how fast an object is traveling; units are distance time-1, e.g. ms-1

Speed-time graphs
Graph showing change of speed with time    
Sprint Constant  

Slope of the graph of the Force applied to a spring against the extra distance extended.

Spring length in equilibrium (natural length) is not included.


stopped, not moving or “at rest”

Time   ???  

to push or drive with force


Turning effect about a pivot under the influence of a force.

Can be clockwise or anticlockwise.

Same as moment and leverage


Unbalanced Forces

forces that are NOT balanced; situation leading to acceleration or deceleration of an object         

Vector Addition of Forces      

speed (Note: velocity is really the measurement of the rate and direction of motion but at Level 1 Science we treat speed and velocity as the same thing)

Velocity Vector Components   Horizontal (v cos θ) and vertical (v sin θ) components  

Weight (Force)

the force on an object caused by gravity


Work (W), J

energy required to make an object move

Process of energy transfer from one form to another.  
Work Done Whenever 'work' is done energy is transferred from one place to another.    


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