Questions from College Physics

Q: In a DNA molecule, the base pair adenine and thymine is

In a DNA molecule, the base pair adenine and thymine is held together by two hydrogen bonds (see Fig. 16.5). Let’s model one of these hydrogen bonds as four point charges arranged al...

Q: A total charge of 7.50 × 10−6 C

A total charge of 7.50 × 10−6 C is distributed on two different small metal spheres. When the spheres are 6.00 cm apart, they each feel a repulsive force of 20.0 N. How much charge is on each sphere?...

Q: Two Styrofoam balls with the same mass m = 9.0

Two Styrofoam balls with the same mass m = 9.0 × 10−8 kg and the same positive charge Q are suspended from the same point by insulating threads of length L = 0.98 m. The...

Q: Harrison traveled 2.00 km west, then 5.00

Harrison traveled 2.00 km west, then 5.00 km in a direction 53.0° south of west, then 1.00 km in a direction 60.0° north of west. (a) In what direction, and for how far, should Harrison travel to ret...

Q: To test hearing at various frequencies, a resonant RLC circuit is

To test hearing at various frequencies, a resonant RLC circuit is connected to a speaker. The resonant frequency is selected by changing a variable capacitor. (a) For an RLC circuit with L = 300 mH,...

Q: Using the three point charges of Example 16.3, find

Using the three point charges of Example 16.3, find the magnitude of the force on q1 due to the other two charges, q2 and q3. [Hint: After finding the force on q1 due to q2, separate that force into x...

Q: (a) Show that the ground-state energy of the

(a) Show that the ground-state energy of the hydrogen atom can be written E1 = −ke2/(2a0), where a0 is the Bohr radius. (b) Explain why, according to classical physics, an electron with energy E1 cou...

Q: An equilateral triangle has a point charge +q at each of

An equilateral triangle has a point charge +q at each of the three vertices (A, B, C). Another point charge Q is placed at D, the midpoint of the side BC. Solve for Q if the total electric force on th...

Q: Section 29.8 states that the total energy released by the

Section 29.8 states that the total energy released by the proton-proton cycle is the same as that released by the carbon cycle CNO-I. Why must the total energy released be the same?

Q: The St. Charles streetcar in New Orleans starts from rest and

The St. Charles streetcar in New Orleans starts from rest and has a constant acceleration of 1.20 m/s2 for 12.0 s. (a) Draw a graph of vx versus t. (b) How far has the train traveled at the end of t...