T2 - Mechanics definitions Flashcards
definitions
Acceleration
Rate of change of velocity
Average speed
Speed over a period of time (total distance / total time)
Displacement
Distance travelled in a particular direction
Drag
Frictional force due to a fluid
Dynamic friction
Friction between two surfaces where there is relative motion
Efficiency
Ratio of work or energy or power output to input
Elastic collision
A collision where kinetic energy is conserved
Energy
The capacity to do work
Force
A push or a pull
Free body diagram
Diagram drawn to show all the forces acting on an object
Impulse
Change in momentum
Inelastic collision
A collision where kinetic energy is lost
Instantaneous speed
Rate of change of distance at one particular time
Law of conservation of momentum
The total linear momentum of a system remains constant provided no resultant external force acts
Linear momentum
Product of mass and velocity
Mass
The amount of matter in an object
Newton’s 1st law
An object continues in uniform motion in a straight line or at rest unless a resultant external force acts
Newton’s 2nd law
the resultant force on an object is proportional to the acceleration (assuming mass is constant)
Newton’s 3rd law
for every action there is an equal but opposite action on another object
Power
Rate at which work is done or energy is transferred
projectile
an object moving through the air under the influence of only one force, gravity
resultant force
the sum of all the forces acting on an object
speed
rate of change of distance
spring constant
a measure of the force required to stretch or compress an object
static friction
the friction between two surfaces where there is no relative motion
terminal velocity
maximum speed attained by falling object, occurs when the downwards weight force is balanced by the upwards air resistance force
translational equilibrium
when the forces acting on an object are balanced
velocity
rate of change of displacement
weight
force of gravity acting on an object
work
a transfer of energy due to a force moving an object through a displacement
