Velocity and acceleration ds v= dt dv ππ£ a= =π£ dt ππ Special cases (a = 0) π = π 0 + π£0 π‘ (const a) v = v0 + a0 t 1 s = s0 + π£0 π‘ + π0 π‘ 2 2 π£ 2 = v02 + 2π0 (π − π 0 ) ρ= π£2 π π£02 π£ = + 2 ∫ π(π ) ππ π‘ π 0 π£ = π£0 + ∫0 π(π‘) ππ‘ s = s0 + π£0 π‘ + π‘ π‘ ∫0 ∫0 π(π‘) ππ‘ ππ‘ πβ = π₯πβ + π¦πβ + π§πββ π£β = π₯Μ πβ + π¦Μ πβ + π§Μ πββ ββ πβ = π₯Μ πβ + π¦Μ πβ + π§Μ π |π£β| = √π₯Μ 2 + π¦Μ 2 + π§Μ 2 SUVAT equation (a const) v = v0 + a 0 t 1 s = s0 + π£0 π‘ + π0 π‘ 2 2 π£ 2 = v02 + 2π0 (π − π 0 ) (π£ + π£0 )π‘ π = 2 Projectile motion π£0π₯ = π£0 cos π π£0π¦ = v0 sin π ππ₯ = 0 π₯ = π₯0 + π£0 π‘ ππ¦ = π0π¦ 1 y = y0 + π£0π¦ π‘ + π0π¦ π‘ 2 Circular motion Dependent motion 2 Cylindrical π« − π system Normal-tangential system π£π−π‘ = π£π’ ββββββββ βββπ‘ π’π = βββ ββββ π’π‘ × ββββ π’π ds v= dt π = π£Μ βββ π’π‘ + π£πΜ ββββ π’π = π£Μ βββ π’π‘ + Rectangular coordinates π 2 - Rope has constant length - Define good datum lines (fixed position) - Find fixed length if possible - Divide the rope into sections if needed πβ = ππ’ βββββπ π£β = πΜ βββββ π’π + ππΜβββββ π’π πβ = (πΜ − ππΜ 2 )π’ βββββπ + (2πΜ πΜ + ππΜ)π’ βββββ π π’π ββββ dy 2 (1+(dx) ) π2 π¦ | 2| ππ₯ Relative motion ππ΅ = βββ βββ ππ΄ + βββββββ ππ΅/π΄ π£π΅ = ββββ ββββ π£π΄ + ββββββββ π£π΅/π΄ ππ΅ = ββββ ββββ ππ΄ + ββββββββ ππ΅/π΄ LT = π π΄ + π π΅ Then π£A + π£π΅ = 0 πA + ππ΅ = 0 βββββπΜ = πΜ βββββ π’ π’π π’πΜ = −πΜβββββ βββββ π’π 1.5 Work and motion dU = πΉ β dπ = πΉ cos π ππ π′ UP>P′ = ∫π ππ = Frictional force (oppose motion) Static |πΉππ πππ₯ | = ππ πΉπ Kinetic |πΉππ | = ππ πΉπ πΉππ > ππ πΉπ velocity decrease πΉππ = ππ πΉπ velocity same πΉππ < ππ πΉπ velocity increase Work by gravitational F Ug = −πβπ¦ = −ππ(π¦2 − π¦1 ) ∫π πΉ dπ = ∫π πΉ cos π ds *Always negative Internal force is zero If particles connected by inextensible cable π π2 πππ‘ ds = 0 ∫π ββββ Work done by force Ug = −ππβπ¦ 1 ππ = − π(π 22 − π 12 ) 2 Uf = −πΉππ βπ Potential energy Vg = ππβ 1 ππ = ππ₯ 2 2 Conservation of energy T1 + π1 + π1>2 = π2 + π2 If (ππ>π = π) T1 + π1 = π2 + π2 Linear momentum β = mv L β Elastic collision Inelastic collision Conservation of momentum: Constant force Conservation of momentum: Avg force Conservation of momentum: ∑ π = π || βπ = π Multiple particles Moment Equilibrium (π« − π) ∑ πΉπ = πππ = π (πΜ − ππΜ 2 ) ∑ πΉπ = πππ = π (2πΜ πΜ + ππΜ) Gravitational force gβ = −9.81πβms−2 F = mgβ π′ Spring force Fs = −ππ₯ k is spring constant x is deviation from rest Equilibrium (x-y-z) Equilibrium (n-t) ∑ πΉπ₯ = πππ₯ = π π₯Μ ∑ πΉπ = πππ = ππ£πΜ ∑ πΉπ¦ = πππ¦ = π π¦Μ = ∑ πΉπ§ = πππ§ = π π§Μ Work by kinetic friction *Against motion> negative Uf = −πΉπ βπ₯ Work by spring π₯2 Us = ∫ −ππ₯ ππ₯ π₯1 1 = − π(π₯22 − π₯12 ) 2 π′ mv 2 π ∑ πΉπ‘ = πππ‘ = ππ£Μ Kinetic energy 1 T = ππ£ 2 2 π1 + π1>2 = π2 π 1 π π£ 2 + ∫π π2 ββββ πΉππ‘ ds + 2 π π1 π1 π π2 2 ββββππ‘ ds = 1 ππ π£π2 ∫ π π π1 π1 m1 vi1 + π2 π£π2 = (π1 + π2 )π£π Angular momentum ββββ π»0 = βββ π0 × ππ£ ββββ0 | = π0 ππ£ sin π |π» = π0 ππ£π π‘2 π‘2 ∫ πΉ dt = πΉ βπ‘ π‘1 π‘1 Principle of angular momentum and impulse π‘ ββββββ H01 + ∫π‘ 2 ∑ ββββ π0 ππ‘ = ββββββ H02 1 π0 = ββββ ∫ πΉ dt = ββββββββ πΉππ£π βπ‘ Conservation of linear momentum ∑ π»01π = ∑ π»02π βββββ0 πH ππ‘ Fixed rotation β Angular displacement θ Angular velocity π β Angular acceleration πΌ vββββπ = π β × πβ ππ = π ββββ β × ββπ£ + πΌ × π If πΌ constant, ω = ω0 + πΌπ π‘ 1 π = π0 + ω0 π‘ + πΌπ π‘ 2 2 ω2 = ω20 + 2πΌπ π General motion Decompose the motion Translation > rotation Force, Moment, Angular Momentum ∑ π» = π€πΌ πΉ = mπ ββββπΊ = ∑π ππ βββ ππ H0 = π€πΌπ βββββ HA = ββββββββ rp⁄A × mv β H πΊ = π€πΌπΊ β = βββββββ ππ⁄π΄ × πΏ ∑ π = πΌπΌ Μ βββββπΊ = ∑ π βββββπΊ π» ππΊ = πΌπΊ α π0 = πΌ0 α (pinned at O) βββββπΊΜ = ∑ βββββ (π» ππΊ X) ππ΄ = πΌπ΄ α (rolling, no slip) Kinetic Energy (ππ + πΌπ→π = π»π ) 1 T = Trotate + ππ‘ππππ πππ‘π TBody = πΌπΌπΆ π€ 2 2 1 1 1 2 2 = πΌπΊ π€ 2 + ππ£πΊ2 = π€ (πΌπΊ + ππ ) 2 2 2 Parallel Axis Theorem Ip = IπΊ + ππ 2 d – distance between P and G ω= π£π΅ −π£π΄ ππ΅/π΄ mv βββ1 = mvβββ2 βββ ββββ2 L1 = L Rigid body motions 2 m1 vi1 + π2 π£π2 = π1 π£π1 + π2 π£π2 π‘ βββββ π0 = βββ π0 × πΉ ∑ ππ ( vβββββπ1 ) + ∑ ∫π‘ 2 ββπΉπ dt = 1 ∑ ππ ( vβββββπ2 ) Instantaneous centre of zero velocity (Point where perpendicular vectors of velocities meet) - Translation - Fixed rotation - General motion ββββB π = ββββ ππ΄ + π β × βββββββββ π£π΅/π΄ + πΌ × ββββββββ ππ΅/π΄ = ββββ ππ΄ − π2 βββββββ ππ΅/π΄ + πΌπββββββββ π΅/π΄ Translation ππ΅ = βββ βββ ππ΄ + βββββββ ππ΅/π΄ π£π΅ = ββββ ββββ π£π΄ ππ΅ = ββββ ββββ ππ΄ Magnitude don’t change Direction don’t change |ππ΅/π΄π‘ | = ππΌ |ππ΅/π΄π | = π2 π vB = ββββ ββββ π£π΄ + π β × ββββββββ ππ΅/π΄ Momentum, impulse and angular momentum β = ππ£ ββ = r × mv πΏ H β = Iw π‘ ββ = π × πΉ = πΌα βββ ββββ2 π L1 + ∑ ∫π‘ 2 ββπΉπ dt = L 1 π‘ βββββββ π»πΊ 1 + ∑ ∫π‘ 2 βββββ ππΊ dt = βββββββ π»πΊ 2 1 π‘2 βββββββ π»π 1 + ∑ ∫π‘ βββββ ππ dt = βββββββ π»π 2 1 Moment of inertia can be added/subtracted Work by forces Ug = −ππββ 1 ππ = − π(π 22 − π 12 ) 2 ββββ2 L1 = L ∫ πΉ ππ‘ = 0 → βββ βββββπΊ ππ‘ = 0 → βββββββ βββββββ π»πΊ 1 = π» ∫ Σπ πΊ2 βββββπ ππ‘ = 0 → π» βββββββ βββββββ ∫ Σπ π 1 = π»π 2 Square moment of inertia 1 IπΊ = ππ2 12 1 Iπ΄ = ππ2 3 G – centre of gravity A – end part of square ββ = π × πΉ π ππ = π(π2 − π1 ) Circle moment of inertia 1 IG = ππ 2 2 IG = πππΊ2 1 I = ππ‘ππ 4 2 πΌ π π 2 ππΊ = √ πΊ = √ ππΊ − radius of gyration Conservation of energy T1 + π1 + U1→2 T1 + π1 = π2 + π2 = π2 + π2 U1→2 – work of nonconservative F Second order differential equations mπ₯Μ + cπ₯Μ + ππ₯ = 0 π 2 − 4ππ > 0 π₯ = π ππ‘ |c| > √4ππ π ππ‘ (ππ2 + ππ + π) π₯ =0 = π΄π π1π‘ + π΅π π2 π‘ −π±√π 2 −4ππ 2 real λs π= 2π Donut moment of inertia 1 IG = π(π 0 + π π )2 2 π 0 – outer radius π π – inner radius 1 IG = ππ‘π(π 04 − π π4 ) 2 m = ππ‘π(π 02 − π π2 ) If no nonconservative F π 2 − 4ππ = 0 |c| = √4ππ π₯ = (π΄ + π΅π‘)π ππ‘ one real λ V = Vπ + ππ 1 Vπ = ππ 2 2 ππ = ππβπΊ π 2 − 4ππ < 0 2 complex λs λ1 = π + ππ λ2 = π − ππ π₯ = π΄π ππ‘ π ππ‘π + π΅π ππ‘ π −ππ‘π = π ππ‘ (πΌπππ ππ‘ + π½π ππππ‘) Formula Booklet MIE100 Final Exam | Revision 2 Apr 14, 2019 | 1 Undamped free vibration – spring motion (horizontal) π π₯Μ + x = 0 π π₯Μ + π€π2 x = 0 wn = √ x = A sin π€π π‘ + π΅ cos π€π π‘ = πΆ sin(π€π π‘ + π) 2π 1 C = √π΄2 + π΅ 2 π = = π π π= Bar pendulum π€π wn = √ 3π 2√2π 2π π ππ − π(π − π0 ) = 0 = πΏππ ππ = π − π0 π Parallel / Series spring Parallel Series 1 = keq k eq = ∑π ππ 1 ∑π πππ π₯Μ + x=0 π wn = 2ππ Square pendulum 3π wn = √ π΅ tan−1 π΄ Vertical spring ∑ πΉπ¦ = 0 π ππ‘ (ππ2 + ππ + π) = 0 π= −π±√π 2 −4ππ π₯ = π΄π π1 π‘ 2π + π΅π π2 π‘ Overdamped (π > ππ ) 2 real, negative λs No vibration c 2 π ( ) − >0 2m π mππ = −mg sin π = −πππ π πΜ + π = 0 π πΜ + π€π2 π = 0 Undamped forced vibration w0 forcing frequency πΉ πΏ0 = 0 static deflection π π F0 π₯Μ + x = sin π€0 π‘ π m x = xπ + xπ xπ = π΄ sin π€π π‘ + π΅ cos π€π π‘ (Transient) xπ = C sin π€0 π‘ (steady) πΉ xππππ₯ = C = (π€ 2 0 2 )π = πΉ0 /π = 2 π€ (1−(π€ 0 ) ) π Damping equation mπ₯Μ + cπ₯Μ + ππ₯ = 0 π₯ = π ππ‘ ππ Undamped free vibration – pendulum motion −mg sin π = πππ‘ π wn = √ π = πθ π Μ Critically damped (π = ππ ) one real λ No vibration πc is smallest c which system won’t vibrate c 2 π ( ) − =0 2m π π₯ = (π΄ + π΅π‘)π ππ‘ π −π€0 πΏ0 π€ 2 (1−(π€ 0 ) ) 2 c 2m ) − π π <0 c x = D [e−2mπ‘ sin(π€π π‘ + π)] π 2 π€π = π€π √1 − ( ) ππ x 2πππ π₯2 √1−( ) ln ( 1 ) = ππ = 2π π€π 1 π€ 2 1 − ( 0) π€π Magnification factor Damping coefficient Fd = −ππ₯Μ (c is damping coefficient) π πc = √ 2π = 2ππ€π π (critical damping coeff) π Underdamped (π < ππ ) 2 complex λs ( π₯ππππ₯ M= = πΉ0 /π Electrical circuit analogy Mass <-> inductance Damp coeff. <-> resistance Spring con. <-> 1/capacitance Force <-> voltage Displacement <-> charge Velocity <-> current π 2 ππ >π Formula Booklet MIE100 Final Exam | Revision 2 Apr 14, 2019 | 2