Physics shortcuts keys IBA 5 TO 15
1. Formulas related to force:
F = ma
F = kx
F = m(vf² – vi²/2S)
F = mv/t
F = md/t²
F = m(vf – vi) /t
F = Area × density × velocity²
F = 1/2 mv²/d
F = 1/2 Pv/d
F = Power/velocity
Fc = mv²/r
Fc = mrw²
Fc/2 = mv²/2r
Fc = 2K.E/r
F = Area × Stress
F = pir² × stress
F = YA × Strain
F = YAl/L
F = pressure × area
F = change in momentum × time interval
F = – 2mVx × Vx/2l
F2 = F1/A1 × A2
F = qE
F = kQ/r²
F = ILB sintheta
F = q (v × B)
F = qE + q(v × B)
2. Formulas related to energy and work
Fd = k.e
mgh = 1/2 mv²
E = 1/2 kx²
E = Ve
E = nhf
E = nhc/lambda
E = Pc
K.e = hf – work function = hf – hf° = hf – hc/w° (here w° is cutt off wavelength)
E = 1/2 Pv
mv²/2r= Fc/2
K.E/r = Fc/2
K.E = Fc×r/2
K.e = 1.5 KT
E = VQ
E = Power × time
E = Fvt
% loss in K.e = v1² – v2²/v1² × 100
% loss in P.e = h1² – h²/h1² × 100
Energy lost due to air friction(Fh) = 1/2mv² – mgh (when body is thrown upward)
Energy lost due to air friction(FS) = mgh – 1/2mv² (when body is thrown downward)
E = 1/2 CV² (capacitor)
E = R × hc (R is Rydberg’ constant)
J = m-¹ × Js ms-¹
hf kalpha x rays = EL – Ek
hf kbeta x rays = EM – Ek
Binding energy = mass defect × c²
W = Fd Costheta
W = nmgh (when person is climbing stairs)
W = n(m+m) gh (when person is climbing stairs with some load)
W = 0mgh + 1mgh + 2mgh + 3mgh ……. (in case of stacking bricks. For ist brick h=0. For 2nd brick h=1. For 3rd brick h=2 and so on)
W = Fd = PA × change in V
W = Q – change in U
Q = mc × change in T
T/273.16 = Q/Q3 (Thermodynamic scale)
W = I²Rt
W = emf×charge
W = VQ
W = 1/2 lF
W = YAl²/2L
W = StressAl²/2Strain
W = PressureAl²/2Strain
W = Fl²/2Strain
3. Formulas related to Power
P = Fv
P = E/t
P = n(mgh/t)
P = Fd/t
P = mv²/2t
4. Formulas related to distance, displacement, velocity and accelration
d = vt
d = at²
d = (vf + vi/2) ×t
d = 5t² (for distance in ‘n’ seconds)
d = 5(2tn – 1) (for distance in ‘nth’ second)
d = 1/2 mv²/F
d = vit + 5t²
d = v × underroot 2H/g
d = vt = x°wt = x°2pi/T × t = x°2pift
x = x° Sin wt
x = x° Sin (underroot k/m) t
vf = vi + at
2as = vf² – vi²
2as = (vi + at)² – vi²
2as = vf² – (vf – at) ²
v = underroot Vfx² + Vfy²
v = Power/Force
v = 2×K.E/momentum (k.e = 1/2 Pv)
v² = 2×Power×time/mass (P = mv²/2t)
v = underroot 2as
v = underroot gr (speed at highest point in a verticle circle)
v = underroot 5gr (speed at lowest point in a verticle circle)
v² = 2FS/m
v² = 2E/m
v² = 2Ve/m
v = eBr/m (velocity of particle under action of magnetic force along circular path)
v² = Force/Area.Density
v = w underroot x°² – x²
v = underroot k/m × underroot x°² – x²
v = x°w (at mean position where x=0)
v = x° underoot k/m
v = v° underroot 1 – x²/x°² (for determining ratio b/w inst. Velocity and maxi. Velocity)
v= x°2pif = x°2pi/T
a = x°w² = x°w.w = vw = v.2pif
Common velocity = m1v1/m1+m2
vi² = Rg/Sin2theta
v = underoot Tension×length/mass
V = 2pi ke²/nh (speed of e- in nth orbit)
Vn = V/n
v = nh/2pimr (lambda = 2pir and lambda=h/p)
ma = kx
a = kx/m (SHM)
a = – gx/l (Simple pendulum)
ac = v²/r
5. Formulas related to wavelength ‘w’
w = v/f
w = 1/wave number
w1 = 2l (when pipe is opened at both ends)
w1 = 4l (when pipe is opened at one end)
Delta w = Us/f (doppler shift)
Wavelength for obs. = w – delta w = v/f – Us/f
w = hc/Ve
w = hc/E
w = h/mv
w = h/P as P = underroot 2mE so
w = h/underroot 2mE (de Broglie wavelength)
w = underroot 150/V A° (short method for de Broglie wavelength. This formula is applicable only for e-)
1/w = RH (1/p²-1/n²)
Wmaxi/Wmini = n²/n²-p² (for determining ratio b /w maxi. Wavelength to mini. Wavelength for series of atomic spectrum)
w = 2pir/n (n is no. of loops in a circle)