BIO SPIDERWEB CONDUCTIVITY . Some types of spiders build webs that consist of threads made of dry silk coated with a solution of a variety of compounds. This coating leaves the threads, which are used to capture prey, hygroscopic —that is, they attract water from the atmosphere. It has been hypothesized that this aqueous coating makes the threads good electrical conductors. To test the electrical properties of coated thread, researchers placed a 5-mm length of thread between two electrical contacts* The researchers stretched the thread in 1-mm increments to more than twice its original length, and then allowed it to return to its original length, again in 1-mm increments. Some of the resistance measurements are shown in the table: *Based on F. Vollrath and D. Edmonds. “Consequences of electrical conductivity in an orb spider’s capture web.” Natunvissenschaften (100:12. December 2013, pp. 1163-69). 25.81 What is the maximum current that flows in the thread during this experiment if the voltage source is a 9-V battery? (a) about 1 A: (b) about 0.1 A: (c) about 1 µ A: (d) about 1 nA.
BIO SPIDERWEB CONDUCTIVITY . Some types of spiders build webs that consist of threads made of dry silk coated with a solution of a variety of compounds. This coating leaves the threads, which are used to capture prey, hygroscopic —that is, they attract water from the atmosphere. It has been hypothesized that this aqueous coating makes the threads good electrical conductors. To test the electrical properties of coated thread, researchers placed a 5-mm length of thread between two electrical contacts* The researchers stretched the thread in 1-mm increments to more than twice its original length, and then allowed it to return to its original length, again in 1-mm increments. Some of the resistance measurements are shown in the table: *Based on F. Vollrath and D. Edmonds. “Consequences of electrical conductivity in an orb spider’s capture web.” Natunvissenschaften (100:12. December 2013, pp. 1163-69). 25.81 What is the maximum current that flows in the thread during this experiment if the voltage source is a 9-V battery? (a) about 1 A: (b) about 0.1 A: (c) about 1 µ A: (d) about 1 nA.
BIO SPIDERWEB CONDUCTIVITY. Some types of spiders build webs that consist of threads made of dry silk coated with a solution of a variety of compounds. This coating leaves the threads, which are used to capture prey, hygroscopic—that is, they attract water from the atmosphere. It has been hypothesized that this aqueous coating makes the threads good electrical conductors. To test the electrical properties of coated thread, researchers placed a 5-mm length of thread between two electrical contacts* The researchers stretched the thread in 1-mm increments to more than twice its original length, and then allowed it to return to its original length, again in 1-mm increments. Some of the resistance measurements are shown in the table:
*Based on F. Vollrath and D. Edmonds. “Consequences of electrical conductivity in an orb spider’s capture web.” Natunvissenschaften (100:12. December 2013, pp. 1163-69).
25.81 What is the maximum current that flows in the thread during this experiment if the voltage source is a 9-V battery? (a) about 1 A: (b) about 0.1 A: (c) about 1 µA: (d) about 1 nA.
Required information
In a standard tensile test, a steel rod of 1 3 -in. diameter is subjected to a tension force of P = 21 kips. It is given that v=
0.30 and E= 29 × 106 psi.
1-in. diameter
P
P
-8 in.
Determine the change in diameter of the rod. (Round the final answer to six decimal places.)
The change in diameter of the rod is -
in.
5.84 ... If the coefficient of static friction between a table and a uni-
form, massive rope is μs, what fraction of the rope can hang over the
edge of the table without the rope sliding?
5.97 Block A, with weight Figure P5.97
3w, slides down an inclined plane
S of slope angle 36.9° at a constant
speed while plank B, with weight
w, rests on top of A. The plank
is attached by a cord to the wall
(Fig. P5.97). (a) Draw a diagram
of all the forces acting on block
A. (b) If the coefficient of kinetic
friction is the same between A and
B and between S and A, determine
its value.
B
36.9°
Chapter 25 Solutions
University Physics with Modern Physics, Volume 1 (Chs. 1-20) (14th Edition)
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
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