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# Physics-GS

### Formulas and Units

Question | Answer |
---|---|

Velocity - acceleration is constant | vf = vi + a t |

Linear Displacement - acceleration constant | xf = vi t + 1/2 a t2 |

Final Velocity | vf2 = vi2 + 2aΔx |

Velocity Units | m/s or cm/s |

Velocity Formula | Δx/Δt=V |

Displacement formula | Δx = xf-xi |

Vector x formula | Fx = F cosӨ |

Vector y formula | Fy = F sinӨ |

How to find Ө using x and y | Ө= tan–1(Fy/Fx) |

Gravitational Formula | FG = GmM/r2 |

Momentum Conservation Formula | m1v1 + m2v2= m1v1 + m2v2 (Elastic collisions) |

Power Formula | P=w/t |

Angular Momentum Formula | L = mvr= Iw L =angular momentum, m =mass of the small object m1v1 + m2v2 v =magnitude of object’s velocity r = separation between the objects |

Centripetal Force Formula | F=mv2/r |

Work formula | W = F d cosӨ W= -μkmgΔx W= TΔxcosӨ W = PΔt |

Kinetic Energy Formula | KE = ½ mv2 ΔKE = fkd energy lost |

Potential Energy Formula | PE = mgh (gravitational) |

Formula for gravity (general) | gravity (general): GmM/r |

Spring Formula - Potential Energy | PE = ½ kx2 (x from equilibrium) |

Heat Formula | Q= cmΔT c=heat capacity of substance m=mass of substance Q=Quantity of heat |

Change in energy formula | ΔE = Q + W W=work E=entropy |

Simple Machine Formula - lever | Torque = lever arm x force |

Spring Periodic Motion Formula | T=2π (SQRroot m/k) |

Pendulum Formula | T=2π (SQRroot L/g) |

Period of object | period = 1/frequency |

Coulomb’s Law | Fc = kqQ/r2 FC (force between q and Q) |

Force felt by Q formula | F = QE (actual force felt by Q) |

Ohmas Law | VR = IR (VR = resistor’s voltage drop) |

Series Resisters Formula | Rt = R1 + R2 |

Parallel Resisters Formula | Rt= (1/R1 + 1/R2)–1 |

Power Lost by each resister | PR = IR 2R = VR 2/R |

Circular Motion | X = R Cos Ө Y = R Sin Ө |

Circular Motion Velocity | V = 2πr/T V = SqRoot g R TAN Ө |

Period Formula | T = mg/CosӨ T = mV2/R |

Moon Gravity | 1/6 that of Earth |

Weight Formula | W = mg |

Distance for planets | d = D/(sqroot moon/M of earth) +1 |

Newton's 3rd Law Formula | Fab = -Fba = W |

Tension Formula | T - Fg = (Fg/g) a EF = T-Fg = ma |

Acceleration with Tension | a = g(F-Fg)/Fg) a = g sin Ө N = -mg Cos Ө |

Freefall formula Drop | Drop = Viy/(G/2) |

Freefall formula Range | Range = (v2/g) sin 2V or d= 1/2 gt2 Max at 45 degrees |

Projectile Formula X component | Vxf = Vxi Vf = Xi+VixΔt Vfx2 = vix2 |

Projectile Formula y component | Vfy=Viy+2yΔt Yf = ViyΔt+1/2ay(Δt)2 Vfy2 = Viy2 + 2ayΔy |

Projectile speed formula | Speed = sqroot Vx2+Vy2 |

Friction Formula Kinetic | fk = μk N |

Friction Formula Static | Fs < μsN |

Friction acceleration Formulas | a = -μkgCos Ө + g Sin Ө |

Drag Force formula | F draV2 Vr = Sqroot (2mg/CpA) |

Terminal Velocity Formula | Vt = sqroot 2mg/CpA |

Hook's Law (springs) | F = -kx |

Work on a spring | Wspring = (kx2/2) - (kxi/2) |

Power Formula | P = FV P (mgh)/(Δt) |

Average Power Formula | Avg P = W/Δt |

Power Units | J/s = 1W Joules per second = Watt 1 hp = 746 Watts |

Earth Data | 6 X 10 24 Kg Radius 6 X 10 6 m |

Univeral Gravitational Potential Energy | Ugrav = mgy ΔUgrav Ugrav = mg (d+h) mg (yf-yi) |

Mechanical Energy | KE+PE = E |

Four Forces | Gravity Electrical Magnetism Strong Nuclear Force Weak Nuclear Force |

Kepler's Formula | T2/r3 |

Orbital Motion | V = sqroot Gm/r satellite speed T2 = (4π2/Gm)r3 |

Momentum Formula | ρ = mv Angular Momentum (ω) |

Rotational Inertia Formula | Rotational Inertia = mr2 |

Impulse formula | I = Ft I = Δp I = pf=pi change momentum F= Δp/Δt If no net force Δp = 0 |

Elastic Collision formulas | Vif = (m1-m2/m1+m2) Vi V2f = (2mi/m1+m2)Vi Δp = 0 ΔE =0 |

Inelastic collisions | h = 1/2 (m1+m2)Vf2/(m1+m2)g ΔP = 0 E not conserved |

Harmonic Motion | 1/2kx2=1/2mv2 (pedulum) |

Restore Force | ԐF = -kx restore ԐF = -k-x compression |

Spring Acceleration | a = (k/m)x |

Tangential SPeed | V = rω V = sqroot ((kx)/m ) |

Potential Inertia -Pendulum | l = mv2 |

Potential Inertia - Hoop | l= 1/2mr2 |

Radian Measures | s/r =Ө or C=2πr s = arc length 1/2 circle = S= 1/2C = 180 degrees s/r = π 2π/360 = 1, 180= S/R = π, 90 = S = 1/4C, S = (30/60)C = 1/12, 360 = 2π |

Center of Mass - Centripetal Force | F = mvr2/r |

Linear Momentum | linear momentum = mv |

angular momentum | angular momentum = mvr |

Center of Mass | rcm = (m1r1+m2r2)/(m1+m2) |

Revolution or cycle | n = S/C = S/(2πr) |

Angular Velocity (ω) | ω= 2πf ω = r(ΔӨ/Δt) V = rω |

Angular Velocity (ω) Units | 1/s or s-1 Hertz (Hz) = 1s-1 radian /s |

Acceleration - using angular | a = v2/r a =rω2 |

Force Normal - angular | FN = mg = Mrω2 ω = sqroot (g/r) |

Revolution | T = period = 1 Revolution 1 rad/s = 9.55 r/min = 0.159 r/s |

Torque | Ft=Mat = Mrα F = T r = R a = Iω |

Moment of Inertia | I = mr2 |

Rotational KE | KErot = 1/2Iω 2 KEtot = KEin+KEout = 1/2mV2+1/2Iω2 K = 1/2lω2 KE=1/2m(Rw)2 = circle |

Angular Momentum | L =r(perpendicular)mv |

Aphelion | V = r(perpendicular) ω Tangential SPeed V = rω Orbit speed |