BIO The Flight of the Dragonflies
Of all the animals you’re likely to see on a summer day, the most ancient is the dragonfly. In fact, the fossil record for dragonflies extends back over 250 million years, more than twice as long as for birds. Ancient dragonflies could be as large as a hawk, and were surely buzzing around the heads of both T. Rex and Triceratops.
Dragonflies belong to the order Odonata (“toothed jaws”) and the suborder Anisoptera (“different wings”), a reference to the fact that their hindwings are wider front-to-back than their forewings. (Damselflies. in contrast, have forewings and hindwings that are the same width ) Although ancient in their lineage, dragonflies are among the fastest flying and most acrobatic of all insects; some of their maneuvers subject them to accelerations as great as 20g.
The properties of dragonfly wings, and how they account for such speed and mobility, have been of great interest to biologists Figure 8-47 (a) shows an experimental setup designed to measure the force constant of Plexiglas models of wings, which are used in wind tunnel tests A downward force is applied to the model wing at the tip (1 for hindwing, 2 for forewing) or at two-thirds the distance to the tip (3 for hindwing, 4 for forewing). As the force is varied in magnitude, the resulting deflection of the wing is measured The results are shown in Figure 8-47 (b) Notice that significant differences are seen between the hindwings and forewings, as one might expect from their different shapes.
79. •• How much energy is stored in the forewing when a force at the tip deflects it by 3.5 mm?
- A. 0.766 mJ
- B. 49.0 mJ
- C. 0.219 J
- D. 170 kJ
Want to see the full answer?
Check out a sample textbook solutionChapter 8 Solutions
Physics (5th Edition)
Additional Science Textbook Solutions
Tutorials in Introductory Physics
University Physics Volume 2
College Physics
An Introduction to Thermal Physics
- (a) What is the order of magnitude of the number of micro organisms in the human intestinal tract? A typical bacterial length scale is 106 m. Estimate the intestinal volume and assume 1% of it is occupied by bacteria. (b) Does the number of bacteria suggest whether the bacteria are beneficial, dangerous, or neutral for the human body? What functions could they serve?arrow_forward(a) Calculate the number of cells in a hummingbird assuming the mass of an average cell is ten times the mass of a bacterium. (b) Making the same assumption, how many cells are there in a human?arrow_forward(a) Suppose that a person has an average heart rate of 72.0 beats/min. How many beats does he or she have in 2.0 y? (b) In 2.00 y? (c) In 2.000 y?arrow_forward
- Impact extinction 65 million years ago over 50% of all species became extinct, ending the reign of dinosaurs and opening the way for mammals to become the dominant land vertebrates. A theory for this extinction, with considerable supporting evidence, is that a 10-kmkm-wide 1.8×1015kg1.8×1015kg asteroid traveling at speed 11 km/skm/s crashed into Earth.Determine the internal energy produced by the collision (a bar chart for the process might help). By comparison, the atomic bombs dropped on Japan during World War II were each equivalent to 15,000 tons of TNT (1 ton of TNT releases 4.2×109J4.2×109J of energy).arrow_forwardNumber 9. Can you explain the process detailed on how to get the solution? I tried multiple times to solve this, but I am still not getting the correct answer.arrow_forwardSmall animals eat much more food per kilogram of body mass than do larger animals. The basal metabolic rate (BMR) is the minimal energy intake necessary to sustain life in a state of complete inactivity. The table lists the BMR in kilocalories per day, the mass, and the surface area for 4 animals. What is the BMR per square meter of the surface area for the mouse?arrow_forward
- Tumor growth Suppose the cells of a tumor are idealized as spheres, each with a radius of 5 μm (micrometers). The number of cells has a doubling time of 35 days. Approximately how long will it take a single cell to grow into a multi-celled spherical tumor with a volume of 0.5 cm3 (1 cm = 10,000 μm)? Assume the tumor spheres are tightly packed.arrow_forward(a) Suppose that a person has an average heart rate of 72.0 beats/mm. How many beats does he or she have in 2.0 years? (b) In 2.00 years? (c) In 2.000 years?arrow_forwardPl:4: this was all information that was given to me. If need I would need to look it up online.arrow_forward
- this is not the actual problem it is just the practice one, I just need a step by step on how to solve it because my teacher did not really teach this in class. thank you for any help you are able to provide.arrow_forwardOne mole of Gold (Au) atom has a mass of 197 g. We know that the density of gold is 19.30 g/cm3 in room temperature. Using those numbers, answer the following questions: a) What is the mass of a single gold atom in kg? b) Assume that gold atoms sit in a perfect cubic crystal structure. Estimate the distance between two gold atoms in meters. c) If we have a gold cube of 6 cm on each side, how many atoms can we fit along the edge of each side of the cube? d) What would be the mass, in kilograms, of the gold cube we discussed in part (c) (measuring 6 cm on each side)?arrow_forwardThe average life expectancy in Japan is 81 years. What is this time in SI units?arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPhysics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning