Calculating Max Voltage Across Resistor Network

[Jstew]

Homework Statement

A 2.8k-ohm and a 2.1k-ohm ersistor are connected in parallel; this combination is connected in series with a 1.8k-ohm resistor. If each resistor is rated at .5W, what is the maximum voltage that can be applied across the whole network?

Homework Equations

Ohm's Law, P=IV

The Attempt at a Solution

I don't even know where to start with this problem.

 

[alphysicist]

When they say that each resistor is rated at 0.5 W, what information can you get from that for each resistor? Remember the expressions for power in a resistor.

 

[Jstew]

P=V^2/R, so V^2=R/2 I don't know what to do with these individual maximum voltages.

 

[alphysicist]

You have P= V^2 / R, and also P = I^2 R for Ohm's law resistors. Since you know the maximum power that each resistor can handle, these give you the maximum voltage and maximum current for each resistor.

So with these constraints, solve the problem as a normal combination of resistor problems, just with an unkown voltage. Then you can use the above constraint to find that maximum voltage for the entire circuit.