# data[].attributes.body
Energy is not created nor destroyed

# data[].attributes.body
Wf= F x d x cos()

Wf= MEf-MEi= -f x d

Wnet= KEf-KEi (work-energy theorem)

Wg= Pegi-Pegf

Wnet=Wg (when only Peg)

# data[].attributes.body
ME = KE + PEg

KE= 1/2 M V²

PEg= mgh

# data[].attributes.body
PEe= 1/2 K x2 (J)

Stiffness:

F=-K X (Xf-Xi) (N.M⁻¹)

# data[].attributes.body
Newtons 1st law:

∑Fext= 0  (no acceleration)

Newtons 2nd law:

∑Fext= ma

Newtons 3rd law:

F1/2=-F2/1

principle of interaction:

equal magnitudes

opposite direction

same line of action

# data[].attributes.body
Particle:

P = m x v (kg.m.s-1)

System:

P= mi vi = mVG

# data[].attributes.body
∑Fext=dp/dt

in a short time:

∑Fext=dp/dt=

pf-pi/tf-ti

# data[].attributes.body
Linear momentum is conserved when system is isolated/sum of external forced applied on system =0

# data[].attributes.body
Elastic: conservation of KEsys (KE=KE')

Inelastic: No conservation of KEsys

# data[].attributes.body
URM (Uniform Rectilinear Motion):

a=0

V= constant

X= Vt+ X0

X-X0=d=Vt

UVRM (Uniform Varied Rectilinear Motion):

UARM: accelerated ( a>0)

UDRM: deccelerated (a<0)

V=at + V₀

X=1/2at² + V⁰t + X₀

V² = V₀ ² + 2ad