Momentary Speed

vmedel=st,vmomentant=dsdtv_{medel}=\frac{s}{t}, \,\,\, v_{momentant}=\frac{ds}{dt}

Momentary Acceleration

amedel=vt=v2V022sa_{medel}=\frac{v}{t}=\frac{v^2-V_0^2}{2s}
amomentan=dvdt=d2xdt2a_{momentan}=\frac{dv}{dt}=\frac{d^2x}{dt^2}

Momentum

p=mv\bf{p} = m \cdot \bf{v} %m:et i fetstil?

Force

F=dpdt=mdvdt=ma\textbf{F} = \frac{d\bf{p}}{dt}= \frac{m \cdot d\bf{v}}{dt} = m \cdot \bf{a}

Work

W=s1s2Fds%W = \int_{x_1}^{x_2} F(x) \,dx W = \int_{s_1}^{s_2} \bf{F} \cdot \,d\bf{s}

Kinetic energy

W[kin]=mv22W_[kin] = \frac{m \cdot v^2}{2}

Potential energy

Wpot=ABFds=Wpot(B)Wpot(A)W_{pot} = -\int_{A}^{B} \bf{F} \cdot \,d\bf{s} = W_{pot}(B)-W_{pot}(A)

Effect

Pmedel=WtP_{medel}=\frac{W}{t}
Pmomentan=dWdtP_{momentan}=\frac{dW}{dt}

Coulumbs law

F=14πϵ0q1q2r2F=\frac{1}{4\pi \epsilon_0}\frac{q_1\cdot q_2}{r^2}

Electric flow

ΦE=EdA\Phi _E = \bf{E}\cdot d\bf{A}

Force on charge in electric field

F=qvBF=q\cdot v\cdot B

Where v is perpendicular to B.

Electric potential energy

W=qEdW=q\cdot E \cdot d

Voltage

U=WqU=\frac{W}{q}

Energy in condensator

W=12QUW=\frac{1}{2}\cdot Q \cdot U

Instantaneous current

Imedel=Qt,i=dqdtI_{medel}=\frac{Q}{t}, i=\frac{dq}{dt}

Ohms law

U=RIU=R\cdot I

Resistivity

R=ρLAR=\rho \frac{L}{A}

Temperature dependence

Rt=R0[1+α(TT0)]R_t=R_0[1+\alpha(T-T_0)]

Where

R0R_0

is the resistance at temperature

T0T_0

Battery

U=ERiIU=E-R_i\cdot I

Electric average power

Pmedel=Wt=UIP_{medel}=\frac{W}{t}=U\cdot I

Series circuit

UTOT=U1+U2+...U_{TOT}=U_1+U_2+...

Resistance in series circuit

RTOT=R1+R2+...R_{TOT}=R_1+R_2+...

Parallel circuit

ITOT=I1+I2+...I_{TOT}=I_1+I_2+...

Resistance in Parallel circuit

1RTOT=1R1+1R2+...\frac{1}{R_{TOT}}=\frac{1}{R_{1}}+\frac{1}{R_{2}}+...

Kirchhoffs law 1

I1+I2+I3+...=0I_1+I_2+I_3+...=0

Kirchhoffs law 2

U1R1IR2IU2=0U_1-R_1I-R_2I-U_2=0

Charge of condensator

Q=CUQ=C\cdot U

Plate capacitor

C=ϵrϵ0AdC=\frac{\epsilon_r\epsilon_0 A}{d}

Energy in Capacitor

W=QU2W=\frac{Q\cdot U}{2}

Capacitance is series circuit

1CTOT=1C1+1C2+...\frac{1}{C_{TOT}}=\frac{1}{C_1}+\frac{1}{C_2}+...

Capacitance is Parallel circuit

CTOT=C1+C2+...C_{TOT}=C_1+C_2+...

Magnetic flow

Φm=BdA\Phi_m=\bf{B}\cdot d\bf{A}