- #1

pokgai

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## Homework Statement

An electric circuit consists of a resistor with a resistance of 12 ohms, a capacitor with

a capacitance of 0:1 farads and an inductor with an inductance of 2 henry connected in

series with a voltage source of 52 cos t volts. Initially the charge on the capacitor is 3

coulombs and the current in the circuit is zero.

(a) Using Kirchho's voltage law, show that the charge q(t) coulombs on the capacitor

at time t seconds satisfies

d2q/dt2 +6dq/dt+5q = 26 cos t

## Homework Equations

V-iR-q/c-Ldi/dt=0

## The Attempt at a Solution

It's pretty basic in that you just plug in the values.

52cos(t)-dq/dt12-q/0.1-2di/dt=0

The only thing I don't understand is the relation with di/dt. I am doing calculus and as such I am not familiar with physics. Just wondering how does that di/dt become d^2q/dt^2.

Cheers