Physics
science that deals with the structure of matter and the interactions between the fundamental consistent of the observable universe. Concerned with all aspect of nature on the scales.
gravity
is a nature phenomenon by which all things with mass or energy brought towards another. 9.81
newtonian mechanics
based on newtons law of motion. Works well for modestly sized objects moving at moderate speed.
Distance
total path length/how far travelled s x t
Displacement
net change in position d=vt. xf-xi+ 1/2(vi x vf)t (average velocity). xf-xi= Vit+1/2at^2 (acceleration with time). Vf^2= Vi^2+2a(xf-xi)
velocity
rate change of displacement Vi + at
friction
When a body is in motion on a surface or in a viscous medium there is resistance to this motion. How high and low the friction is will depend on the coefficient. The lower this value the more slippery the surface becomes.
SI units
the international system of units.
work
when force is acted upon an object to cause displacement of that object. Work is the transfer energy to the system.W= Fdcos0
Kinetic energy
energy of motion KE= 1/2mv^2
motions in 2 dimension
motion is only one dimension so we need to consider other dimensions. r= xi+yj
Potential energy
An object with kinetic energy has the capacity to do work on another object, but if the object is nor yet in motion, i.e the kinetic energy is 0. An object has the ability. to store energy as a result of its position. Two types of potential energy, gravitational and elastic.
gravitational PE
The energy stored in an object as a result of its vertical position. PEgrav= Ug= mgh
acceleration
rate change in velocity. ax= v/t= Vxf-Vxi/ tf-ti
Free falling object
an object moving under the influence of gravity alone.
air resistance
this is from collision of the surface of the object with air molecules. We can consider the acceleration of the object as a balance between two forces, gravity and air.
Laws of motion
First law - Inertia =a body at rest will remain at rest, and a body in motion will remain in motion unless it is acted upon by external force.
Second law - Force = the force acting on an object is equal to the mass of that object times the acceleration.
third law- reaction= for every action, there is an equal and opposite reaction.
Force
is any interaction that, when unopposed, will change the motion of an object. Two types, contact forces and action at a distance force. F= ma.
Elastic potential energy
an object may have the ability to store energy as a result of stretching or compressing. Us= 1/2kx^2 Ki= 0 (not yet in motion) Us= 0 kf= 1/2mv^2
Mechanical energy
the sum of potential and kinetic energy. when no energy is added or removed from a system.
Conservative forces
the total energy in the system is equal to the sum of kinetic energy and potential energy only when conservative forces are in play. eg. gravity Ei= Ef
non-conservative forces
in the presence of non-conservative forces there can be a change in the total mechanical energy. eg. friction as it is acting to resist motion and hence reduces the total mechanical energy. Ei+E= Ef
power
work is were force causes displacement however, this does not give any indication as to how long it may take for the displacement to occur. Power is the rate at which work is done. p= W/t. sum of forces I power = F-f-mg = f+mg
Angular and linear equations
the linear velocity vector of a rotating object will always be tangential to the circular path.
