Science—Physics 1 Equations
Back to Physics Formulas and Derivations
1-D Motion
Δx=12(vi+vf)tvf=vi+atΔx=vit+12at2v2f=v2i+2aΔx}x−dirΔy=12(vi+vf)tvf=vi+atΔy=vit+12at2v2f=v2i+2aΔy}y−dira=−9.8ms2 (free fall)
Vectors
Radj=RcosθRopp=RsinθR=√R2adj+R2oppθ=tan−1RoppRadj
Projectile Motion
vxi=vicosθvxi=vxΔx=vysinθ}x−dirvyi=vysinθΔy=viyt+12at2vfy=viy+atv2fy=v2iy+2aΔy}y−dirθ=tan−1vfyvfx (impact angle)R=v2isin(2θ)gH=(visinθ)22gt=2visinθg}Special Case: hi=hf
Forces and Torque
∑⇀F=0∑Fx=0∑Fy=0∑τ=0}static∑⇀F=m⇀a∑Fx=max∑Fy=may∑τ=Iα}dynamicFg=mg (force due to gravity)fs≤μsFnfs=μkFn}frictional forces⇀Rliquid=−b⇀v⇀Rair=12DρAv2vterm=√2mgDρA}restrictive forcesF=Gm1m2r2 (Gravitational force between two objects)τ=Frsinθ
Work and Energy
W=FΔxcosθΔK=12mΔv2 (Kinetic Energy)ΔUg=mgΔh (Gravitational P.E.)ΔUs=12kΔx2 (Elastic P.E.)Wnet=ΔKWnc+Wc=ΔK}Work Energy TheoryWc=−ΔU (Conservative)Wnc=−fkd (Non−Conservative)
Impulse and Momentum
⇀p=m⇀v⇀I=⇀FΔt⇀pi=⇀pf⇀pi=⇀pfm1v2i+m2v2i=m1v2f+m2v2f (inelastic and elastic)m1v2i+m2v2i=(m1+m2)vf (perfectly inelastic)v1i−v2i=−(v1f−v2f) (elastic)
Angular Momentum
⇀L=Iω⇀L=⇀r×⇀p⇀Li=⇀Lf
Angular Motion
ωav=12(ωi+ωf)ωf=ωi+αtΔθ=ωit+12αtω2f=ω2i+2αΔθ}Angular Equations of Motion⇀rcm=n∑i=1mi⇀rim1+m2+m3+...+mn (Center of Mass)vt=rωat=rαac=v2rac=rω2Fc=mac}Circular MotionI=n∑imir2iIp=Icm+mr2Iz=Ix+Iy}Moment of Inertia
Moments of Inertia of Homogeneous Rigid Objects
ICM=MR2 (Hoop or thin cylindrical shell)ICM=12M(R21+R22) (Hollow cylinder)ICM=12MR2 (Solid cylinder or disk)ICM=112M(a2+b2) (Rectangular plate)ICM=112ML2 (Long, thin rod with rotation axis through center)ICM=13ML2 (Long, thin rod with rotation axis through end)ICM=25MR2 (Solid sphere)ICM=23MR2 (Thin spherical shell)
Rolling Without Slipping
Δs=rΔθvcm=rωacm=rαω=vcmrKr=12Iω2 (Rolling Kinetic Energy)K=12mv2+12Iω2 (Total Kinetic Energy)
Simple Harmonic Motion (SHM)
F=−kx (Hooke′s Law)a=−kmx (SHM acceleration)v=±√km(A2−x2) (SHM velocity)T=2π√mk (Period of a Spring)ω=√km (Angular Frequency)x=Acos2πftv=−Aωsin2πfta=−Aω2cos2πft}SHM Equations of Motion