Title | Dynamics Cheat sheet |
---|---|
Course | Dynamics |
Institution | University of Massachusetts Lowell |
Pages | 4 |
File Size | 186.4 KB |
File Type | |
Total Downloads | 89 |
Total Views | 146 |
equation sheet...
3 ´u= du F=G Mm {G =6.67 ×10−11 m } 2 r dt s kg r A → B (B w . r . t A)=r B =r B−r A A
dv a ( s)=v =¿ ads=vdv ds Rectilinear Motion:
B
]
dr =´v B =´v B−´v A → v´ B=´v A + v´ B dt A A dv a= = a´ B =´a B−´a A → a´ B= a´ A + a´ B dt A A v=
∑ F´ x =m a x : ∑ F´ y =m a y : ∑ F´ z =m az
Normal & Tangential 2
∑ F´ t=m a t=m ´v : ∑ F´ n=m an=m vρ : ∑ F´ b=0 s=rθ →ds=rdθ → vdv=ads =at rdθ v
θ
v0
θ0
∫ vdv=∫ a t rdθ Cylindrical
∑ F´ r=m a r=m ( ´r −r θ´ 2) ´ r´ θ´ ) [ corriollis acc 2 r´ θ´ ] ∑ F´ θ=m aθ= m ( r θ+2 ∑ F´ z =m az =m ( z´ )
1 s= a t t2 + v 0 t +s 0 2 v =´s =a t t+ v o 2 2 v =v 0 +2 at (s− s0 ) a´ =v´ u´ t +u´´ t v=at u´ t +an u´ n 2
v an = (centripital Acc) ρ
( )
dy 2 32 ⌋ dx
| | 2
d y d x2
Cylindrical
r x =r cos θ , r y =r sin θ [θ rad ] , z=z ,
rad ] v r =´r , v θ=r θ´ , vz=´z ´θ=angular vel[ s ar =r´ −r θ´ 2 , a θ=r ´θ+2 r´ θ´ , az = z´ Relative Motion: Independent Translating
( )
−1
∅=tan
Normal & Tangential
ρ=
A
Kinetics: Cartesian
1 2 s x =x=s x 0 + v x 0 t + a t 2 1 s y = y =s y 0 +v y0 t+ a t2 2 v x 0=v 0 cos θ , v y 0 =v 0 sin θ v x = s´x =at+ v x0 , v y = s´y =at+ v y 0 ´ x´ = v´ , a y = s´y = y´ = v´y ax= sx= x u |u|= √ ux +u y ;θ=tan−1 y ux
⌊ 1+
A
2 S B +h+ S A =l T S´ A + 2´S B=0=¿ 2 v B =−v A 2 aB =−a A
Curvilinear Motion: Cartesian
s´ = ρθ´
A
Dependent
1 2 s= a t +v 0 t+s 0 2 ds v = =at +v 0 dt dv a= dt 2 2 v =v 0 +2 a(s −s 0 )
at =´v =´s ,
[
´r B =´r A + r´ B → r´ B =r´ B− r´ A , ´r B=− r´ A
r dr dθ
3 )=θ 100 dU =F´ ∙ d ´r = F´ ds cos ( θ ) [ N ∙ m ] { +→∈direction of action tan −1 (
Work: Note 3% slope=
r2
s2
[Variable F ] U 1 →2=∫ F´ ∙ d r´ =∫ F cos (θ ) ds r1
s1 s2
[Constant Force straight ] U 1 → 2=F c cos ( θ ) ∫ds s1 z2
[Weight :+ ↓ ] U 1 →2=∫−wdz=−w ( z 2− z 1 ) z1 s2
[Spring ]U 1→ 2=∫ (−ks ) ds= s1
−1 2 2 k (s 2 −s 1 ) 2
Principle of Work and Energy (Forces on particle expressed in terms of displacement)
m at ds=mvdv → s2
v2
1
1
[
1 ∫ ∑ F´ t ds=∫ mvdv= 2 m (v 22−v21) →U 1 → 2=T 2−T 1 T = v s T 1 +U 1 → 2=T 2[ initial k . e+work=Final k . e ]
Power:
P=
∆U J d r´ ´ = F ∙ ´v =Fv cos θ watt= = N ∙ m = F´ ∙ s dt ∆t s
[
Efficiency:
]
Impact: Stages 1.)
Before Impact ( t < t 0) =initial momentum for particale 2.)
power ouput energy output = ε= energy input power input
t2
Deformation Impulse I AB (effect of A on B )=∫ P A dt , t1
Potential Energy: Gravitational
t2
m A v a 1−∫ Pdt =m A v
V g =wh [ above datum ]=− wh[ below datum ]
t1 t2
Elastic:
1 2 V e= k s 2 V´ =V´ g + V´ e ´ g 1+ V´ e1 ) − ( V ´ g 2+ V´ e2 ) U 1 →2= V´ 1−V´ 2= ( V
t1
3.)
t2
t1
4.) Restitution Impulse
Conservation of Energy:
t2
m A (v)−∫ Rdt =m A v A 2
T U 1−2 ∑¿ ¿ (¿ ¿ 1+V 1)+¿ ¿ T 1 +( V e1 +V g 1 ) =¿
t1 t2
I R=∫ Rdt=m A (v ) −m A ( v A 2) : I D >I R t1
´L A 2=m v´ A 2 : L´ B 2 =m v´ B 2 5.) After Impact Conservation of linear momentum
T 2 +( V e2 +V g 2 )
Disp Vel
Rectilin angular S ϴ V ω
Acc
A
α
Cartesian
cylindrical
(x , y , z ) (vx , v y , vz ) (a x , a y , az )
(r ,θ , z ) ( vr , v θ , v z ) (a r , aθ , az )
Principle of Impulse and Momentum: (Forces on particle expressed in terms of time)
d ´v d (m v´ ) ´ ´ = a=m ∑ F=m dt dt t2
t1
L A + LB =L AB m A ( v A 1) + m B ( v B 1) =m A( v A 2 )+ m B (v B 2 ) t2
∫ Pdt=m A ( v A 1 )−m A (v) t1 t2
∫Rdt=m A ( v ) −mA ( v A 2 ) t1
Coefficient of restitution
∫ Rdt = v−v A 2 ∫ Pdt v A 1 −v ∫ Rdt = v B 2−v e B= ∫ Pdt v −v B 1 e A=
v2
t2
∑ F´ dt =d ( m v´ ) →∫ ∑ F´ dt=∫ md v´ =∫ ∑ F´ dt=m v´ v1
t1
t2
m v´ 1+∫ ∑ F´ dt=m v´ 2 → ´L1+ ´I 1 → 2=L´ 2
e=
t1 t2
v B 2−v A 2 Relative velocity of seperation = v A 1 −v B 1 Relative velocity of approach
Angular Momentum and Impulse
´I =∫ ∑ F´ dt [Linear impulse ] t1
]
´L=m v´ linear momentum acts∈´v (kg ∙ m ) s Cartesian:
[ L1´i+ L1 ´j+ L1 k´ ]+ [I ´i+ I ´j + I k´ ]=[ L2 ´i+ L2 ´j + L2 ´k ] t2
m v x 1 +∫ F x dt=m v x2 (same format for y , z) t1
Maximum Deformation
I M =∫ Pdt= ( m A +m B ) v
´ g 2+ V´ e2 ) − ( V ´ g 1+ V´ e1 ) U 2 →1= V´ 2−V´ 1= ( V
[
∫ Pdt =m A ( v A 1 )−m A (v)
I D =¿
particle∈ x . y planeabout point O (z axis) ¿ = H [Scalar Form] ( O) z (r )( mv ) [ r is moment arm ] ´ O= ´r × m ´v [Vector Form] H ´ O=¿ H ´´ moment about O=time rate change H M O ∑¿
´ ´ FO =¿ LO resultant force = time rate change of L ∑¿ t2
t2
´ ) dt ´ O dt=∫ (r´ × F angular impulse∫ M t1
t1
a´ A → acceleration of base point A ω ´ → angular velocity of body α´ → angular acceleration of body r´ B → position vector directed ¿ A ¿ B A
Principle of Angular Impulse and Momentum
´ O )2 ( H´ O) 1+∑∫ M O dt= ( H ∑ ( H´ O )1=∑ ( H´ O ) 2 [conservation of ang momentum] Planar kinematics of Rigid Body Translation [position]
r´ B =´r A +´r B A
[velocity] v´ B=´v A [acceleration] a´ B=´a A Rotation (about a fixed axis)
[angular position ] θ= 1 α t2 +ω 0 t +θ0
2 dθ [angular velocity ] ω= =αt +ω 0 dt 2 2 ω =ω0+2 α (θ−θ0 ) dω [angular acceleration ] α= : αdθ =ωdω dt (for the point P from point O)
´v B=v´ A +
(a P )t =αr , ( aP )n=ω r ( ´ ) = ´ ´ ( ´ ) +=´Ω´ × ´( ´ ´ rB / A) v´ B=´v A +( v´ B / A ) xyz (
)
2 →a´ P = ( α´ × r´ P / O )−ω r´ P / O
General plane (relative motion analysis)ri
r´ B =´r A +´r B A
(
´ ´ [Velocity] v´ B=´v A +´v B =´v A + ω× r B
A
)
v´ B → velocity of B v´ A → velocity of base point A ω ´ → angular velocity of body r´ B → position vector directed ¿ A ¿ B
v´ B → absolute velocity of B measured ¿ XYZ v´ A → velocity of origin A of x , y , z referance measured ¿ the XYZ referance ( v´ B / A) xyz → velocity of B w . r . t A observed ¿ the x , y , z referance (Ω´ ) →insitanious angular velocity of moving referance frame x , y , z r´ B / A → position vector of B w . r .t A [acceleration]
A
[Acceleration]
´ (v´ B/ A ) xyz+ (a´ B/ A ) xyz ´ × ´r B / A) ] +2 Ω× a´ B=´a A +(Ω´´ ×´r B/ A ) +[ ´Ω×( Ω
a´ B=´a A +( a´ B / A ) t +( a´ B / A ) n a´ B=´a A +( α´ ×´r B/ A) + [ ω× ´ ( ω×´ ´ r B/ A )] ´a B=a´ A +( α´ × r´ B/ A ) −ω 2 r´ B A
a´ B → acceleration of B
d r´ B / A dt
d r´ B / A = ´v B / A +( Ω´ × r´ B / A ) dt
2
A
r´ B =´r A + r´ B / A ^ y ^j r´ B / A=x Bi+ B [velocity]
s P =θr , v P=v O +v P /O =v O +ωr , v´ P= v´ O + v´ P /O =´v O + ω ´ × r´ P/ O
[Position]
Relative Motion Analysis using Rotating Axes [Position]
a´ B = acceleration of B, measured from the X, Y, Z reference
a´ A
= acceleration of the origin A of the x, y, z reference, measured from the X, Y, Z reference (a´ B / A )xyz ,( v´ B / A) xyz=¿ acceleration and velocity of B with respect to A, as measured by an observer attached to the rotating x, y, z reference
´´ , ´ = angular acceleration and angular velocity of Ω Ω the x, y, z reference, measured from the X, Y, Z reference r´ B / A = position of B with respect to A...