Here are some of the most important formulas and conversions you will need to know for the Physics Regent and/or Physics Subject SAT. Even though I have a link to the actual reference table, I am going to explain some formulas in greater detail.
1kg = 2.2lbs
1 quarter = 5g = 0.005kg
sinθ=opp/hyp
cosθ=adj/hyp
tanθ=opp/adj
Ff = μFN
v = d/t = circumference/period = 2πr/T
ac = v^2/r
Fc = mac = mv^2/r
Fg = Gm1m2/r^2
W = Fd
Mechanical Energy: PEg+PEs+KE
Total Energy: PEg+PEs+KE+Q
Springs: PEs = kx^2/2 and Fs = kx
Conservation of Energy: PEg+PEs+KE+Q = PEg+PEs+KE+Q
Work-Energy Theorem: W = ΔET
Inelastic Collision: m1v1+m2v2 = (m1+m2)vf
Elastic Collision: m1v1+m2v2 = m1v1+m2v2
Fe = kq1q2/r^2
E = Fe/q
Resistance of a wire: R = ρL/A where A = πr^2
Series Circuit: Req = R1+R2+R3 and VT = V1+V2+V3
Parallel Circuit: IT = I1+I2+I3 and (1/Req) = (1/R1)+(1/R2)+(1/R3)
Resistance: R = V/I
Mechanical Power: P = W/t = Fd/t = Fv
Electrical Power: P = VI = I^2R = V^2/R
Law of Reflection: θi = θr
Total Internal Reflection: sin θC = n2/n1
E = mc2 (only use if E is in Joules and m is in kg)