End-of-chapter Problem Errata
Cutnell & Johnson, Introduction to Physics 8e
Chapter 2
8. An 18-year old runner can complete a 10.0-km course with an average speed of 4.42 m/s. A 50-year old runner can cover the same distance with an average speed of 4.12 m/s. How much later (in seconds) should the younger runner start in order to finish the course at the same time as the older runner?
Chapter 4
9. An electron is a subatomic particle (m=9.11 x 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +8.25 x 106 m/s to a final velocity of +3.12 x 107 m/s while traveling a distance of 0.051 m. The electron's acceleration is due to two electric forces parallel to the x axis: F1=1.20 x 10-14 N, and F2, which points in the -x direction. Find the magnitudes of (a) the net force acting on the electron and (b) the electric force F2.
Chapter 11
6. A gold prospector finds a solid rock that is composed solely of quartz and gold. The mass and volume of the rock are, respectively, 12.0 kg and 4.00 x 10-3 m3. Find the mass of the gold in the rock.
64. Consult Multiple-Concept Example 15 to review the concepts on which this problem depends. Water flowing out of a horizontal pipe emerges through a nozzle. The radius of the pipe is 1.9 cm, and the radius of the nozzle is 0.53 cm. The speed of the water in the pipe is 0.75 m/s. Treat the water as an ideal fluid, and determine the absolute pressure of the water in the pipe.
Chapter 18
59. Refer to Concept Simulation 18.3 at www.wiley.com/go/global/cutnell for a perspective that is useful in solving this problem. Two spherical shells have a common center. A-1.6 x 10-6 C charge is spread uniformly over the inner shell, which has a radius of 0.050 m. A+5.1 x 10-6 C charge is spread uniformly over the outer shell, which has a radius 0.12 m. Find the magnitude and direction of the electric field at a distance (measured from the common center) of (a) 0.20 m, (b) 0.10 m, and (c) 0.025 m.
Chapter 20
67. A 60.0-Ω resistor is connected in parallel with a 100.0-Ω resistor. This parallel group is connected in series with a 20.0-Ω resistor. The total combination is connected across a 18-V battery. Find (a) the current and (b) the power delivered to the 100.0-Ω resistor.
Chapter 26
52. A slide projector has a converging lens whose focal length is 105.00 mm. (a) How far (in meters) from the lens must the screen be located if a slide is placed 108.00 mm from the lens? (b) If the slide measures 24.0 mm x 32.0 mm, what are the dimensions (in mm) of its image?
116. Consult Interactive Solution 26.116 at www.wiley.com/go/global/cutnell to review the concepts on which this problem depends. A camera is supplied with two interchangeable lenses, whose focal lengths are 30.0 and 150.0 mm. A woman whose height is 1.60 m stands 9.00 m in front of the camera. What is the height (including sign) of her image on the image sensor, as produced by (a) the 30.0-mm lens and (b) the 150.0-mm lens?
Chapter 31
44. Two radioactive nuclei A and B are present in equal numbers to begin with. Three days later, there are three times as many A nuclei as there are B nuclei. The half-life of species B is 1.50 days. Find the half-life of species A.