Concept explainers
Biomechanical engineers have developed micromechanical devices for measuring blood flow as an alternative to dye injection following angioplasty to remove arterial plaque. One experimental device consists of a 300-μm-diameter, 2.0-μm-thick silicon rotor inserted into blood vessels. Moving blood spins the rotor, whose rotation rate provides a measure of blood flow. This device exhibited an 800-rpm rotation rate in tests with water flows at several m/s. Treating the rotor as a disk, what was its
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Essential University Physics: Volume 1 (3rd Edition)
Additional Science Textbook Solutions
Lecture- Tutorials for Introductory Astronomy
College Physics: A Strategic Approach (3rd Edition)
Essential University Physics (3rd Edition)
Physics: Principles with Applications
College Physics
The Cosmic Perspective (8th Edition)
- The tires of a car make 80 revolutions as the car reduces its speed uniformly from 93.0 km/hkm/h to 59.0 km/hkm/h. The tires have a diameter of 0.88 mm.arrow_forwardThere is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a hand crank. The outer wall of the cylinder is perforated with small holes. You put the wet leaves in the container and turn the crank to spin off the water. The radius of the container is 14.9 cm. When the cylinder is rotating at 1.28 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall? _____ m/s^2arrow_forwardA ceiling fan with 89-cm-diameter blades is turning at 60 rpm . Suppose the fan coasts to a stop 25 s after being turned off. What is the speed of the tip of a blade 10 s after the fan is turned off? Through how many revolutions does the fan turn while stopping?arrow_forward
- In 2010, the Sikorsky's X2 helicopter became the world's fastest helicopter, flying at 249 miles per hour. When flying over 230 mph, the rotor speed is reduced from 446 to 360 RPM to keep tip speed below Mach 0.9. If each one of the six rotor blades is about 4.02 m long, how fast is the blade tip actually moving when the rotational speed is 360 RPM?arrow_forwardA turntable with a mass of 12 kg and a radius of 1.8 meters spins at a constant angular velocity of 140 rpm. A 3-kg brick with a width of 15 cm and a depth of 30 cm falls onto the turntable, so the brick's center of mass is one meter away from the turntable's center. If there's no friction between the brick and turntable and they eventually spin at the same angular speed, what is their final angular speed, in rev/min or in rad/s? Justify your answer with your rationale and equations used. Moments of Inertia: I disk MR? for rotation about its center of mass parallel to the z-axis. = Iblock 5M (W2 + D² ) for rotation about its center of mass parallel to the z-axis.arrow_forwardA turntable with a mass of 12 kg and a radius of 1.8 meters spins at a constant angular velocity of 140 rpm. A 3-kg brick with a width of 15 cm and a depth of 30 cm falls onto the turntable, so the brick's center of mass is one meter away from the turntable's center. If there's no friction between the brick and turntable and they eventually spin at the same angular speed, what is their final angular speed, in rev/min or in rad/s? Justify your answer with your rationale and equations used. Moments of Inertia: Idisk = MR² for rotation about its center of mass parallel to the z-axis. Iblock = M (W² + D²) for rotation about its center of mass parallel to the z-axis.arrow_forward
- The Bunchberry flower has the fastest moving parts ever observed in a plant. Initially, the stamens are held by the petals in a bent position, storing elastic energy like a coiled spring. When the petals release, the tips of the stamen act like medieval catapults, flipping through a 60° angle in just 0.30 ms.to launch pollen from anther sacs at their ends. The human eye just sees a burst of pollen; only high speed photography reveals the details. We can model the stamen tip as a 1.0 mm long, 10µg rigid rod with a 10µg anther sac at the end. Although oversimplifying, we'll assume a Pollen Pollen Anther sac constant angular acceleration. A. How large is the "straightening torque"? (you may assume the torques created by the gravity 1.0 mm Stamen force are minimal compared to the straightening torque, and can be ignored. B. What is the speed of the anther sac as it releases its pollen? Initial configuration Final configurationarrow_forwardThere is a clever kitchen gadget for drying lettuce leaves after you wash them. It consists of a cylindrical container mounted so that it can be rotated about its axis by turning a hand crank. The outer wall of the cylinder is perforated with small holes. You put the wet leaves in the container and turn the crank to spin off the water. The radius of the container is 12.2 cm. When the cylinder is rotating at 2.45 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall? Number Units #arrow_forwardA single-engine helicopter has two rotors; a main rotor and a tail rotor. The main rotor has a diameter of 15.4 m and rotates at the rate of 420 rev/min while the tail rotor with a diameter of 1.68 m rotates at 4000 rev/min. what are the speeds, in m/s, of the tips of each rotor? main rotor speed m/s tail rotor speed m/sarrow_forward
- An electric fan makes 300 revolutions per minute. If it comes to a stop after 12 secs, what is the angular acceleration of the fan?arrow_forwardYour roommate is working on his bicycle and has the bike upside down. He spins the 54.0 cmcm -diameter wheel, and you notice that a pebble stuck in the tread goes by three times every second. What is the pebble's speed? What is the pebble's acceleration?arrow_forwardA car with 58-cm-diameter tires accelerates uniformly from rest to 20 m/s in 10 s. How many times does each tire rotate?arrow_forward
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningUniversity Physics (14th Edition)PhysicsISBN:9780133969290Author:Hugh D. Young, Roger A. FreedmanPublisher:PEARSONIntroduction To Quantum MechanicsPhysicsISBN:9781107189638Author:Griffiths, David J., Schroeter, Darrell F.Publisher:Cambridge University Press
- Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningLecture- Tutorials for Introductory AstronomyPhysicsISBN:9780321820464Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina BrissendenPublisher:Addison-WesleyCollege Physics: A Strategic Approach (4th Editio...PhysicsISBN:9780134609034Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart FieldPublisher:PEARSON