91Ó°ÊÓ

(a) What is the mass of a large ship that has a momentum of \(1.60 \times 10^{9} \mathrm{kg} \cdot \mathrm{m} / \mathrm{s},\) when the ship is moving at a speed of \(48.0 \mathrm{km} / \mathrm{h} ?\) (b) Compare the ship's momentum to the momentum of a 1100 -kg artillery shell fired at a speed of \(1200 \mathrm{m} / \mathrm{s}\).

Use the characteristics of the Coulomb force to explain why capacitance should be proportional to the plate area of a capacitor. Similarly, explain why capacitance should be inversely proportional to the separation between plates.

Will a negative charge, initially at rest, move toward higher or lower potential? Explain why

Can different equipotential lines cross? Explain.

Suppose you want a capacitor bank with a total capacitance of \(0.750 \mathrm{~F}\) and you possess numerous \(1.50 \mathrm{mF}\) capacitors. What is the smallest number you could hook together to achieve your goal, and how would you connect them?

A \(0.500 \mathrm{~cm}\) diameter plastic sphere, used in a static electricity demonstration, has a uniformly distributed \(40.0 \mathrm{pC}\) charge on its surface. What is the potential near its surface?

Give the reason why a dielectric material increases capacitance compared with what it would be with air between the plates of a capacitor. What is the independent reason that a dielectric material also allows a greater voltage to be applied to a capacitor? (The dielectric thus increases \(C\) and permits a greater \(V .)\)

(a) What is the energy stored in the \(10.0 \mu \mathrm{F}\) capacitor of a heart defibrillator charged to \(9.00 \times 10^{3} \mathrm{~V} ?\) (b) Find the amount of stored charge.

What is the relationship between voltage and energy? More precisely, what is the relationship between potential difference and electric potential energy?

In open heart surgery, a much smaller amount of energy will defibrillate the heart. (a) What voltage is applied to the \(8.00 \mu \mathrm{F}\) capacitor of a heart defibrillator that stores \(40.0 \mathrm{~J}\) of energy? (b) Find the amount of stored charge.