Physics Exam Equation Sheet 1D Kinematics 2D Kinematics Quadratic Formula x = vo t + ½ a t2 x = vox t + ½ ax t2 y = voy t + ½ ay t2 a t2 + b t + c = 0 vx = vox + ax t vy = voy + ay t t v = vo + a t v2 = vo2 + 2 a x b b 2 4ac 2a vx2 = vox2 + 2 ax x vy2 = voy2 + 2 ay y Forces Work and Energy ΣFx = m ax ΣFy = m ay ΣFr = m ac & ac = v2/r W=Fd W = ½ k x2 W = ΔKE (work) (spring work) ΔPE + ΔKE = O ΔPE + ΔKE = Wnc ΔPE= PEf – PEo ΔKE = KEf – KEo Ef - Eo = Wnc Ef = Eo E = KE + PE PE = m g h KE = ½ m v2 PE = ½ k x2 (ideal) (with losses) W=mg Ff = μ N Fs = -k (x-xo) F = k (x-xo) (weight) (friction) (from spring) (applied on a spring) Power P=W/t P=F v (linear) (linear) P = τ (rotational) Hp = τ n / 63025 (τ in inlb) kW = τ n / 9550 (τ in Nm) (with losses) (ideal) (height) (velocity) (springs) Rotational Kinematics Rotational Dynamics Power Drives θ = ωo t + ½ α t2 ω = ωo + α t ω2 = ωo2 + 2 α θ ac = r ω2 at = r α vt = r ω = 2πr/T s=rθ τ=rF Στ = 0 Στ = I α τ 1/t1 = τ 2/t2 f = 1/T ω = 2πf (T is period) (τ is torque) Wr = τ θ KEr = ½ I ω2 Etot=½ m v2 + ½ I ω2 + mgh L=Iω ΔL = 0 ΔL = Lf – Lo (τ is torque & t is # of teeth) (equilibrium) (motion) (angular momentum) (gears and chains) t1 ω1 = t2 ω2 t1 n1 = t2 n2 τ 1/r1 = τ 2/r2 (belts) r1 ω1 = r2 ω2 r1 n1 = r2 n2 Physics Exam Equation Sheet Linear Momentum SHM ΔP = 0 ΔP = Pf – Po x = A cos ( ω t ) v = - A ω sin ( ω t ) a = - A ω2 cos ( ω t ) = - ω2 x p=mv impulse = F Δt = m vf – m vo m m2 v o1 v f1 1 m m 2 1 2m1 v o1 v f2 m1 m 2 elastic collision & vo2 = 0 f = 1/T ω = 2πf ω k m v k 2 (A x 2 ) m E = ½ k x2 Center of Mass Xcm m x m i i i Sound I=P/A I = P / 4 π r2 (point source) β = (10dB) log (I /Io) where Io = 1x10-12 from math... y = 10 x & x = log 10 y (T is period) (mass on spring)