A lightweight electric car is powered by a series combination of ten 12.0-V batteries, each having negligible internal resistance. Each battery can deliver a charge of 142 A · h before needing to be recharged. At a speed of 84 km/h, the average frictional force due to air drag and rolling friction is 1.22 kN. (a) What must be the minimum power delivered by the electric motor if the car is to travel at a speed of 84 km/h? kw (b) What is the total charge, in coulombs, that can be delivered by the series combination of ten batteries before recharging is required? kC (c) What is the total electrical energy delivered by the 10 batteries before recharging? MJ (d) How far can the car travel (at 84 km/h) before the batteries must be recharged? km (e) What is the cost per kilometer if the cost of recharging the batteries is 9 cents per kilowatt-hour? $/km

When a Leyden jar is charged by a hand generator (Fig. 27.1, page 828), the work done by the person turning the crank is stored as electric potential energy in the jar. When a capacitor is charged by a battery, where does the electric potential energy come from?

Rank the potential energies of the lour systems of particles shown in Figure OQ25.5 from largest to smallest. Include equalities if appropriate.

What does it mean when a force is negative? What does it mean when the potential energy is negative?

Review A system consists of a planet and a star, with the planet in an elliptical orbit. As the planet orbits, which of these quantities change because they depend on the mass of the planet? Explain your answers. a. Gravitational potential energy b. Gravitational potential c. Kinetic energy d. Gravitational force e. Gravitational field

A large household air conditioner may consume 15.0 kW of power. What is the cost of operating this air conditioner 3.00 h per day for 30.0 d if the cost of electricity is $0.110 per kW h?

(a) What is the available energy content, in joules, of a battery that operates a 2.00-W electric clock for 18 months? (b) How long can a battery that can supply 8.00104 J run a pocket calculator that consumes energy at the rate of 1.00103 ?

A person in good physical condition can put out 100 W of useful power for several hours at a stretch, perhaps by pedaling a mechanism that drives an electric generator. Neglecting any problems of generator efficiency and practical considerations such as resting time: (a) How many people would it take to run a 4.00-kW electric clothes dryer? (b) How many people would it take to replace a large electric power plant that generates 800 MW?

The temperature near the center of the Sun is thought to be 15 million degrees Celsius ( 1.5107oC ) (or kelvin). Through what voltage must a singly charged ion be accelerated to have the same energy as the average kinetic energy of ions at this temperature?

A parallel-plate capacitor has square plates of side s = 2.50 cm and plate separation d = 2.50 mm. The capacitor is charged by a battery to a charge Q = 4.00 C, after which the battery is disconnected. A porcelain dielectric ( = 6.5) is then inserted a distance y = 1.00 cm into the capacitor (Fig. P27.88). Hint: Consider the system as two capacitors connected in parallel. a. What is the effective capacitance of this capacitor? b. How much energy is stored in the capacitor? c. What are the magnitude and direction of the force exerted on the dielectric by the plates of the capacitor? Figure P27.88