Your car's 31.5 W headlight and 2.15 kW starter are ordinarily connected in parallel in a 12.0 V system. What power would one headlight and the starter consume if connected in series to a 12.0 V battery? (Neglect any other resistance in the circuit and any change in resistance in the two devices. Answer to the nearest 0.1 W.)

figure the resistance of each first R=power/12

then in series, add the resistances, and then power=12^2/Rt

This is acually ignoring a lot of characteristics of motors, as in the motor, effective resistance is not a constant, but depends on the voltage applied, and how fast the motor is turning and developing back EMF. But ignore all this for now.

im still not getting it.

To determine the power consumed by one headlight and the starter when connected in series, we first need to understand how to calculate the power in a circuit.

The power in an electric circuit can be calculated using the formula: P = V * I, where P represents power (in watts), V represents voltage (in volts), and I represents current (in amperes).

In this scenario, we know that the system voltage is 12.0 V, so we will use this value in our calculations. However, we do not have the current directly given, so we need to find it before calculating the power.

Since the devices are connected in series, the total resistance in the circuit will be the sum of the individual resistances. To calculate the total resistance, we need to use Ohm's law, which states that the current flowing through a circuit is equal to the voltage divided by the resistance: I = V / R.

Let's start by calculating the resistance of each device:

1. Headlight: Since we are given the power of the headlight (31.5 W) and the system voltage (12.0 V), we can use the formula P = V^2 / R, where R represents resistance. Rearranging the formula, we get R = V^2 / P. Plugging in the values, we have: R_headlight = 12.0^2 / 31.5.

2. Starter: Similar to the headlight, we can calculate the resistance of the starter using the given power (2.15 kW) and system voltage (12.0 V): R_starter = 12.0^2 / 2.15.

Now that we have the resistance values for both devices, we can calculate the total resistance in the circuit by summing the individual resistances: R_total = R_headlight + R_starter.

Once we have the total resistance, we can calculate the current flowing through the circuit using Ohm's law: I = V / R_total.

Finally, we can calculate the power consumed by the series-connected headlight and starter: P_total = V * I.

Follow these steps to find the power consumed by one headlight and the starter when connected in series:

1. Calculate the resistance of the headlight using the formula: R_headlight = 12.0^2 / 31.5.
2. Calculate the resistance of the starter using the formula: R_starter = 12.0^2 / 2.15.
3. Calculate the total resistance by summing the individual resistances: R_total = R_headlight + R_starter.
4. Calculate the current flowing through the circuit using Ohm's law: I = 12.0 / R_total.
5. Finally, calculate the power consumed by the headlight and starter in series: P_total = 12.0 * I.

Note: Remember to round the final answer to the nearest 0.1 W as requested in the question.