Physics for engineer/Motion

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Motion is cause by a force interacts with matter to make matter move from one place to another place . Strength to kick a ball to move from place A to place B

Chracteristics of motion

Velocity

Speed indicates the speed of motion to travel a distance over time

v=st

Acceleration

Acceleration indicates the change of speed of motion

a=vt

Distance

Distance indicates the length of travel path of motion

s=vt

Force

A physcial quantity intaeracts with matter to perform a task

F=ma

Work

Work indicates the capability of a force to perform a task

W=Fs=Fvt

Energy

Energy indicates the capability of a force to perform a task over time

E=Wt=Fst=Fv

Formula

Tính Chất Ký Hiệu Công thức
Time t t
Acceleration a vt
Speed v v
Distance s vt
Force F ma
Work W Fs=Fvt
Energy E Wt=Fst=Fv

Types of Motion

Linear Motion

Linear Motion represents motion that follows straight line without changing its direction


Accelerationn of linear motion passes through 2 points (to,vo)(t,v)

a=vvotto=ΔvΔt

From above

Δv=aΔt
Δt=vvoa

Speed of linear motion

v=vo+aΔt
vo=vaΔt

Distance of linear motion

s=voΔt+12ΔvΔt=Δt(vo+Δv2)=Δt(vo+aΔt2)=Δt(vaΔt2)=(vvoa)(2vo+vvo2)=v2vo22a

Fromm above

v2=vo2+2as

Linear Motion with acceleration not equal zero

a=vvotto=ΔvΔt
v=vo+aΔt
s=voΔt+12ΔvΔt=Δt(vo+Δv2)=Δt(vo+aΔt2)=Δt(vaΔt2)=v2vo22a


a=vvotto=vvot
v=vo+at
s=t(vo+at2)


a=v0t0=vt
v=at
s=12vt=12at2

Linear Motion with acceleration equal zero

a=ΔvΔt=vvotto=0
v=vo
s=vot

Linear Motion with acceleration equal constant

a=g
v=gt
s=gt2

Curve Motion

Continous motion

Average acceleration for curve motion

a=Δv(t)Δt=v(t+Δt)v(t)(t+Δt)t

Average distance for curve motion

s=Δt[v(t)+Δv(t)2]


As Δt0

Instantanous acceleration for curve motion

a(t)=limΔt0Δv(t)Δt=ddtv(t)=v'(t)

Instantanous distance for curve motion

s(t)=limΔt0[v(t)+Δv(t)2]Δt=v(t)dt=V(t)+C

Bounded continous motion

Distance for curve motion from A to B

sab=abf(x)dx=F(b)F(a)
sab=baf(x)dx=F(a)F(b)
savg=1baabf(x)dx
srms=savg

Circular Motion

Full circle

s=2π
v=2πt=2πf=ω
a=ωt

Arc of circle

α=ωωotto=ΔωΔt
ω=ωo+aΔt
θ=ωoΔt+12ΔωΔt=Δt(ωo+Δω2)=Δt(ωo+αΔt2)=Δt(ωαΔt2)=ω2ωo22α


s=rθ
v=rω
a=rα

Oscillation

Horizontal Oscillation

Oscillation of spring in the horizontal direction

Fa=Fx
mg=kx
a=kmx=βx=d2dt2x
x=Asin(ωt)
ω=β=km

Vertical Oscillation

Oscillation of spring in the vertical direction

Fg=Fy
mg=ky
g=kmy=βy=d2dt2y
y=Asin(ωt)
ω=β=km

Inclined Oscillation

Oscillation of pendulum in the titlted direction

Fθ=Fθ
mg=lθ
g=lmθ=βθ=d2dt2θ
θ=Asin(ωt)
ω=β=lm

Wave

From above, oscillation generates sin wave that process wave equation and wave function

Wave equation and wave function

Wave form

Wave equation

f'(t)=βf(t)

Wave function

f(t)=Asinωt
ω=β

Formula of motions

Moment

v < C

Tính Chất Ký Hiệu Công thức
Time t t
Speed v v
Acceleration a vt
Distance s vt
Force F ma=mvt=pt
Work W Fs=Fpts=pv
Energy E Wt=pvt=pa
Moment p mv=Ft

v = C

Tính Chất Ký Hiệu Công thức
Time t t
Speed v C=λf
Acceleration a Ct
Distance s Ct
Force F ma=pt=hλt=hfλ
Work W Fs=pC=hf
Energy E Wt=pCt
Moment p hλ

v > C

Tính Chất Ký Hiệu Công thức
Time t t
Speed v v
Acceleration a vt
Distance s vt
Force F ma=mvt=βpt
Work W Fs=Fpts=βpv
Energy E Wt=pvt=βpa
Moment p mβp

Linear motion

Inclined Linear motion

Tính Chất Ký Hiệu Công thức
Time t t
Acceleration a ΔvΔt=vvotto
Speed v vo+aΔt
Distance s (vo+aΔt)Δt
Force F ma=mΔvΔt
Work W Fs=F(vo+aΔt)Δt
Energy E Wt=F(vo+aΔt)

Vertical Linear motion

Tính Chất Ký Hiệu Công thức
Time t t
Acceleration a g=MGh2
Speed v gt
Distance s gt2
Force F mg=mMGh2
Work W mgh=mMGh
Energy E mght==mMGht

Horizontal Linear motion

Tính Chất Ký Hiệu Công thức
Time t t
Acceleration a vt
Speed v v
Distance s vt
Force F ma=mvt
Work W Fs=Fvt
Energy E Wt=Fv

Curve motion

v(t) =

Tính Chất Ký hiệu Công thức
Distance s v(t)dt
Time t t
Speed v v(t)
Acceleration a ddtv(t)
Force F ma=mddtv(t)
Work W Fs=Fv(t)dt
Energy E Wt=Ftv(t)dt

s(t) =

Tính Chất Ký hiệu Công thức
Time t t
Distance s s(t)
Speed v ddts(t)
Acceleration a d2dt2s(t)
Force F ma=md2dt2s(t)
Work W Fs=Fvt=pv=pddts(t)
Energy E Wt=Fv=pa=pd2dt2s(t)

Circular motion

Full circle motion

Tính Chất Ký Hiệu Công thức
Time t t
Distance s 2π
Speed v 2πt=2πf=ω
Acceleration a ωt
Force F ma=mωt
Work W Fs=Fvt=pv=pω
Energy E Wt=Fv=pa=pωt

Circular Arc motion

Tính Chất Ký Hiệu Công thức
Time t t
Distance s rθ
Speed v rω
Acceleration a rα
Force F ma=mrα
Work W Fs=Fvt=pv=prω
Energy E Wt=Fv=pa=prωt

Oscillation motion

Horizontal Osicllation

Fa=Fx
ma=kx
a=βx=d2dt2x
x=Asinωt
ω=β=km


Vertical Osicllation

Fg=Fy
mg=ky
g=βy=d2dt2y
y=Asinωt
ω=β=km

Inclined Osicllation

Fg=Fθ
mg=lθ
g=βθ=d2dt2θ
θ=Asinωt
ω=β=lm

Wave motion

Wave function

f(t)=Asinωt

Wave equation

f'(t)=βf(t)
ω=β
Tính Chất Ký Hiệu Công thức
Time t t
Distance s λ
Speed v λf=ω
Acceleration a ωt
Force F ma=mωt
Work W Fs=Fvt=pv=pω
Energy E Wt=Fv=pa=pωt

Force and Motion

From Newton laws

Force equals zero . Matter is stationary
Force is not zero . Matter is in motion
Sum of the forces equal zero . Matter is in equilibrium


Force of momentum travels horizontaly

Fp=mVt=pt
p=mv=Ft
m=pv=Ftv
v=pm=Ftm
t=mvF=pF

Force of momentum travels verticaly

O
|
V
Fg=mg=mMGh2
g=MGh2
h=MGg

Equilibrium for hang in the air

Fp > Fg Matter stays above
Fp < Fg Matter stays below
Fp = Fg Matter stays hang in the air


Fp=Fg
mvt=mg
v=gt
t=vg
a=g=MGh2
h=MGa