(1) What power (in kW) is supplied to the starter motor of a large truck that draws 250 A of current from a 24.5 V battery hookup? ________kW.
(2) A battery of voltage V delivers power P to a resistor of resistance R connected to it. By what factor will the power delivered to the resistor change if the following changes are made? Give your answers as a factor of the original power P.
(a)The resistance is changed to 3.50R. ________P
(b) The voltage of the battery is now 3.50V, but the resistance is R. ________P
(c) The resistance is 3.50R and voltage is 3.50V. ________P
(d) The resistance is 3.50R and the voltage is V/3.50. ________P
(3) You and your housemate have an argument over the cost of the electric bill. You want to turn off the outside porch light before going to bed each night. Your housemate wishes to keep the light on from 6:00 PM each evening to 6:00 AM the next morning and says that this will not add any significant amount to the electric bill. If the porch light bulb is a 75 W bulb, how much will your housemate's plan contribute to the electric bill each month? Take the number of days in a month as 30 and the average cost of electricity is 13.8¢/kW · h. _________$
(4) Assuming 95.0% efficiency for the conversion of electrical power by the motor, what current must the 12.0-V batteries of a 833-kg electric car be able to supply to do the following?
(a) accelerate from rest to 25.0 m/s in 1.00 min ________A
(b) climb a 200-m high hill in 2.00 min at a constant 25.0 m/s speed while exerting 443 N of force to overcome air resistance and friction _______A
(5) Certain heavy industrial equipment uses AC power that has a peak voltage of 526 V. What is the rms voltage? _______V
(6) What is the peak current through a 588 W room heater that operates on 230 V AC power? ________A
(7) When an AC source is connected across a 24.0 Ω resistor, the output voltage is given by Δv = (140 V)sin(50πt). Determine the following quantities.
(a) maximum voltage _______V
(b) rms voltage ________V
(c) rms current _______A
(d) peak current _______A
(e) Find the current when t = 0.0045 s. ________A
(8) An AC voltage source is connected to a resistor R = 1.90 102 Ω. The output from an AC voltage source is given by the expression V = (2.00 102 V) sin 2πft.
(a) What is the rms voltage across the resistor? ________V
(b) What is the rms current flowing through the resistor? ________A
(9) An AC voltage source and a resistor are connected in series to make up a simple AC circuit. If the source voltage is given by V = V0 sin(2πft) and the source frequency is 21.7 Hz, at what time t will the current flowing in this circuit be 73.0% of the peak current? ________ms