Physics help needed - 10 points for first answer (just answer what you know is fine)?

7. A 24 W resistor is used to control the speed of a vacuum cleaner plugged in to a 110 V circuit. If 90 V of energy is lost in the resistor, determine (a) the voltage left to run the vacuum cleaner, and (b) the current flowing through the resistor.

8. When a toaster is plugged into a 120 V outlet it draws 8.0 A of current. Determine the total resistance of the toaster.

9. Determine the electrical resistance of a clothes dryer that is plugged into a 240 V outlet and draws 18 A of current.

10. When you make a telephone call the electrical signal created by your voice travels down telephone wires, which typically have a resistance of approximately 250 W. Calculate the current flowing in the telephone wires assuming that your phone generates a voltage of 9.5 V.

7) a) subtract 90V from 110V

b) Power = Current * Voltage

8) Ohm's law: V = IR

9) V = IR

10) Power = Current * Voltage

Whoever wrote these problems was inexcusably sloppy in their terminology. Big thumbs down for your teacher! 250W is POWER, not resistance. 90V is potential or voltage, not energy. 24W is POWER, not resistance. It makes it hard to tell what they REALLY meant. I'd assume that the units are correct and the words are wrong.

HUH?

7....A 24 W resistor is incorrect.
If you mean 24 惟 (ohms), voltage is not affected as the resistor will be in series (in line), while voltage is measured across the circuit.
The current through the resistor = V/R = 110/24 = 4.6A.
8....Resistance (R) = V/A = 120/8 = 15惟.
9....Again, V/A = 240/18 = 13.33惟.
10..Here again, the resistance cannot be in Watts.
If you mean ohms then, A = V/R = 9.5/250 = 0.04A

(W = V x A)

As the first answer said, some of the symbols used here don't make sense, in some of the places (especially #10) where "W" is used, 惟, or writing out ohm, would fit the question better. A bit of trivia, and a possible explanation, the upper case Greek letter omega 惟 is the common symbol for resistance, but the lowercase does look like a w (蠅) however, in standard practice the lower case omega is not used for resistance.

Another complication is that actual manufactured resistors do have a power rating so 24W could refer to a resistor of unknown resistance but with a power rating of 24 watts, however, knowing only the power rating does not give one enough information to determine the current because in normal practice one does not operate a resistor at it's maximum power rating. Now if the problem had stated that the resistor is in fact dissipating 24 watts (in which case at least a 30w rating should be used) then one can determine the current with Ohms law, since 90v are bing lost in the resister, 90v/24w = 3.75 amps. On the other hand if the resistance is 24 ohms, the answer is actually the same 90v/24ohms = 3.75 amps. So it probably sounds like I was just nitpicking above, but my point is the wording is poor,