Discharging a capacitor through a resistor

[slain4ever]

Homework Statement

A 2 micro F capacitor with an initial charge of 5.1 micro C is discharged through a 1.3 kohm resistor
a) calculate the current though the resistor 9ms after the resistor is connected across the terminals of the capacitor.
b) what charge remains on the capacitor after 8ms
c) what is the maximum current in the resistor?

Homework Equations

This is what i need help with

my book gives me:
q(t) = Q e ^ -t/RC
I(t) = (Io) e^-t/RC

im not 10% sure how to use this/these formulas to get the answers,

The Attempt at a Solution

my guess is that Q is 5.1 * 10^-6
R = 1.3 * 10^3
C = 2 * 10 ^ -6
t = 9ms (a), 8ms (b)

but i don't know what q and t on the left side of the equation mean nor what units it is in

 

[ehild]

q(t) means the charge on the capacitor at time t after the resistor has been connected. I(t) is the current flowing in the circuit (so across the resistor, too, at time t.

ehild

 

[slain4ever]

oh so its just like f(x)

and what are the units?

also is time in seconds?

 

[ehild]

Yes, they are functions of the time (t) like f(x) is function of x. The unit of t is s (second) , q is charge, its unit is C (coulomb) and I is current, its unit is A (ampere)

ehild