Physics Formulas and Conversions, Study notes of Physics

Download Physics Formulas and Conversions and more Study notes Physics in PDF only on Docsity! g=9.8 m/s2 100 cm=1 m 39.37 inches=1 m 1 km=1000 m 12 inches=1 foot 5280 feet=1 mile 1 kg = 1000 g 1 hour = 3600 s G=6.7 10-11 Nm2/kg2 Comparison between metric and English units of Force: 1 lb (pound) = 4.45 N Useful formulas: Formulas: Don’t forget d = v t !!!!! water freezes at 32 oF = 0 oC = 273 K water boils at 212 oF = 100 oC = 373 K x-x0 = v0x + (1/2)axt2 y-y0 = v0y + (1/2)ayt2 2ax (x – x0) = vx2 – v0x2 2ay (y – y0) = vy2 – v0y2 v = v0 + at F=ma Fgravity = GmM/r2 where ` G=6.7 10-11 Nm2/kg2 a = v2/r circumference of a circle: 2r, where r is the radius Linear: Espring = ½ kx2 Fspring=-kx Egrav. potential = mgh (h is the height) EKinetic Energy = ½ mv2 p(the momentum) = mv (remember, p and v are vectors, so p has both size and – if it’s important – direction) If there are no external forces (→ momentum is conserved) and the collision is elastic (→ energy is conserved) if mass m1 hits a stationary mass m2 then v1final = v1initial (m1-m2)/( m1+m2) and v2final = v1initial (2m1)/( m1+m2) Rotational: s=rθ vlinear=r alinear=r Remember, use radians for θ, , and  in these and all formulas below. 1 rotation = 360 o (<- don’t use!) = 2 radians Erot. Kin. Energy = ½ I2 L(angular momentum)=I I(moment of Inertia) is for a point mass a distance ‘r’ from the axis of rotation=mr2 (If you need a moment of inertia for a special problem – as long as that’s not the question – you will be given it.) torque = I also, torque = F times ‘lever arm’, where ‘lever arm’ is the distance of closest approach to the axis of rotation of the Force vector extended forwards and backwards. Density is represented by the Greek letter ρ. ρ=M/V, where M is the mass of the object and V is the volume the object takes up. 1 Hz = 1 cycle/second ; vsound=343 m/s f=/2 f=1/T v= λf f =(k/m)1/2 β (in dB) = 10 log(I/I) = 10 log(I/I0), where I0 is the reference sound intensity 10-12 W/m2 Doppler formula: for the source moving away from the observer: f’ = f/(1 + vsource/vsound) for the source toward the observer: f’ = f/(1 - vsource/vsound) Electrical: V=IR, power loss = I2R (I is current thru R) = V2/R (V is voltage drop across R) ; Rseries = R1 + R2 + R3 + … ; 1/Rparallel = 1/R1 + 1/R2 + 1/R3 + …. Relativity: L=L0 * (1-v2/c2)1/2 t=t0/(1-v2/c2)1/2 F=qvB) = 10 log(I/I (force on a moving charge in a magnetic field) the charge on 1 electron is -1.6 x 10-19 C, on 1 positron +1.6 x 10-19 C