2- Mechanics Flashcards
Acceleration (definition)
The rate of change of velocity in a particular direction. Vector quantity.
Acceleration (equation)
a = v/t
Angular velocity (definition)
The rate of change of angle of an object undergoing uniform circular motion at constant speed
Angular velocity (equation)
w = ∆θ/∆t
Law of conservation of linear momentum
The total linear momentum of a system of interacting particles remains constant provided there is no resultant external force (i.e. the system is isolated)
Centripetal acceleration (definition)
Acceleration of an object moving at constant speed in uniform circular motion. Speed is constant but direction of velocity is changing, so it’s accelerating
Centripetal acceleration (equation 1)
a = v^2/r
Centripetal acceleration (equation 2)
a = 4π^2r/T^2
Elastic collision
Collisions in which no energy is gained or lost, ie. Collisions between atoms and molecules.
Energy
The work that has been done on a body. Also equal to the amount of work that the body is capable of doing.
Gravitational potential energy
mg∆h
Impulse
The resultant force acting on the object times time for which this force acts. It is equal to change of momentum of the object. Vector quantity
Impulse (equation)
F∆t and m∆v
Inelastic collision
Collisions in which the objects involved in the collision lose energy (e.g. to thermal energy or to sound). All laboratory collisions are inelastic.
Kinetic energy
1/2mv^2
p = mv
Linear momentum
Newton’s first law (definition)
A body in motion stays in motion unless an external force acts
Newton’s second law (equation 1)
F = ma
Newton’s second law (equation 2)
F = ∆p/∆t
Newton’s third law (definition)
Two interacting bodies exert equal and opposite forces on each other
Power (equation)
P = ∆W/∆t
Power
Rate of doing work, which is the same as the rate of transferring energy. Scalar quantity.
Translational equilibrium
When the resultant force on the object is zero. Object is either at rest or moving with constant (uniform) velocity in a straight line
Work
Force times component of displacement in direction which force acts
Work (equation 1)
Force x distance
Work (equation 2)
W = Fscosθ
W = mg
Weight
Momentum, energy
In an elastic collision which out of: momentum, energy, are conserved?
Principle of conservation of energy
Energy cannot be created or destroyed, it just changes from one type to another
Work (equation 3)
W = ∆Ek
