Physics, Conservation laws, & Oscillations Flashcards
Rate of change
How much a quantity will change in a given amount of time
Velocity
The rate of change of an object in a certain direction
Speed
The velocity in the direction of motion
- always positive
change in position = velocity x (elapsed time)
Newton’s first law
The velocity in each direction is constant in the absence of interactions
-ie, objects move at a constant speed in a fixed direction
Conserved quantities
Quantitative properties of a physical system that remain constant in time
- energy
- momentum
- spin
Mass
The energy of an object at rest
Kinetic energy
The energy that an object has due to its motion
Momentum
Energy carried by a moving object in the direction it is moving
momentum = mass x velocity
Quantifies how hard it is to stop the object’s movement
If objects interact,
the sum of the momenta before = the sum of the momenta after
An equal strength push on two different objects will lead to the same change in momentum
Spin (angular momentum)
Related to mass, size, and period of rotation
Conservation of angular momentum: an isolated spherical object of fixed size will spin with a fixed period or rotation about a fixed axis
Force
Quantifies the instantaneous strength of a push or pull
Force = rate of change of momentum (in absence of other forces)
Newton’s second law
A force of 1 Newton will cause a 1kg object to change its velocity by 1 m/s in 1 second
1 Newton = 1 kg m/s /s
Force of gravity
A downward force with magnitude
F = M x g
M = mass; g = 9.8 m/s /s
Rules for predicting positions and velocities
Newton’s third law
When there is a force from object A on object B, there should be an equal opposing force from object B on object A
(equal in strength, opposite in direction)
Mechanical equilibrium
An object is in mechanical equilibrium if it is at rest and the net force on the object is zero
