You are an electrician for the city where you live. You get a call about a parking lot at baseball field where the lamp posts keep shutting off, due to the circuit breaker. A circuit breaker is a switch that automatically stops the flow of electricity due to a current being too strong or some other dangerous situation. You've been called in to figure out why the circuit is breaking.
One of the most common formulas dealing with electricity is called Watt's Law. This algebraic equation states that "p" (power measured in watts) is equal to "V" (the voltage measured in volts ) times "I" (the current measured in amps).
P = VI
Here is what you know about the baseball field parking lot situation.
• There are 9 lamp posts connected to this circuit.
• Each lamp post has a 400 watt lamp installed.
• The circuit is 120-volt and 20-amp.
How many watts does 9 lampposts require?