Concept explainers
Spin-Dry Dragonflies Some dragonflies splash down onto the surface of a lake to clean themselves. After this dunking, the dragonflies gain altitude and then spin rapidly at about 1000 rpm to spray the water off their bodies. When the dragonflies do this “spin-dry,” they tuck themselves into a “ball”. If they spin with a linear speed of 2.3 m/s, and curl into a ball with a radius of 1.1 cm, what is the centripetal acceleration they produce?
Figure 6-62
Problem 59
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
EBK PHYSICS
Additional Science Textbook Solutions
Genetic Analysis: An Integrated Approach (3rd Edition)
Applications and Investigations in Earth Science (9th Edition)
Campbell Biology (11th Edition)
College Physics: A Strategic Approach (3rd Edition)
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Human Anatomy & Physiology (2nd Edition)
- You are working during your summer break as an amusement park ride operator. The ride you are controlling consists of a large vertical cylinder that spins about its axis fast enough that any person inside is held up against the wall when the floor drops away (Fig. P6.7). The coefficient of static friction between a person of mass m and the wall is s, and the radius of the cylinder is R. You are rotating the ride with an angular speed suggested by your supervisor. (a) Suppose a very heavy person enters the ride. Do you need to increase the angular speed so that this person will not slide down the wall? (b) Suppose someone enters the ride wearing a very slippery satin workout outfit. In this case, do you need to increase the angular speed so that this person will not slide down the wall? Figure P6.7arrow_forwardCasting of molten metal is important in many industrial processes. Centrifugal casting is used for manufacturing pipes, bearings, and many other structures. A cylindrical enclosure is rotated rapidly and steadily about a horizontal axis, as in Figure P7.62. Molten metal is poured into the rotating cylinder and then cooled, forming the finished product. Turning the cylinder at a high rotation rate forces the solidifying metal strongly to the outside. Any bubbles are displaced toward the axis so that unwanted voids will not be present in the casting. Suppose a copper sleeve of inner radius 2.10 cm and outer radius 2.20 cm is to be cast. To eliminate bubbles and give high structural integrity, the centripetal acceleration of each bit of metal should be 100g. What rate of rotation is required? State the answer in revolutions per minute. Figure P7.62arrow_forwardA particle of dust lands 45.0 mm from the center of a compact disc (CD) that is 120 mm in diameter. The CD speeds up from rest, and the dust particle is ejected when the CD is rotating at 90.0 revolutions per minute. What is the coefficient of static fraction between the particle and the surface of the CD?arrow_forward
- Nearly all conventional piston engines have flywheels on them to smooth out engine vibrations caused by the thrust of individual piston firings. Why does the flywheel have this effect?arrow_forwardA car traveling on a flat (unbanked), circular track accelerates uniformly from rest with a tangential acceleration of a. The car makes it one-quarter of the way around the circle before it skirts oil the track. Front these data, determine the coefficient of static friction between the car and the track.arrow_forward(a) What is the angular momentum of the Moon in its orbit around Earth? (b) How does this angular momentum compare with the angular momentum of the Moon on its axis? Remember that the Moon keeps one side toward Earth at all times. (c) Discuss whether the values found in parts (a) and (b) seem consistent with the fact that tidal effects with Earth have caused the Moon to rotate with one side always facing Earth.arrow_forward
- At its peak, a tornado is 60.0 m in diameter and carries 500 km/h winds. What is its angular velocity in revolutions per second?arrow_forwardSaturns ring system forms a relatively thin, circular disk in the equatorial plane of the planet. The inner radius of the ring system is approximately 92,000 km from the center of the planet, and the outer edge is about 137,000 km from the center of the planet. The mass of Saturn itself is 5.68 1026 kg. a. What is the period of a particle in the outer edge compared with the period of a particle in the inner edge? b. How long does it take a particle in the inner edge to move once around Saturn? c. While this inner-edge particle is completing one orbit abound Saturn, how far around Saturn does a particle on the outer edge move?arrow_forwardDynamics II: Motion in a Plane 8-5 CHAPTER 8 11. A coin of mass m is placed distance r from the center of a turntable. The coefficient of static friction PSS between the coin and the turntable is us. Starting from rest, the turntable is gradually rotated faster and faster. At what angular velocity does the coin slip and "fly off"? a. Begin with a pictorial representation. Draw the turntable both as seen from above and as an edge 8.1 view with the coin on the left side coming toward you. Label radius r, make a table of known information, and indicate what you're trying to find. OnT Tadiuset Mass z m fz els N b. What direction does f point? Explain. c. What condition describes the situation just as the coin starts to slip? Write this condition as a mathematical statement. d. Now draw a free-body diagram of the coin. Following Problem Solving Strategy 8.1, draw the free- body diagram with the circle viewed edge on, the r-axis pointing toward the center of the circle, and the z-axis…arrow_forward
- 6arrow_forwardCurrent Attempt in Progress There 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 wațer. The radius of the container is 13.6 cm. When the cylinder is rotating at 2.24 revolutions per second, what is the magnitude of the centripetal acceleration at the outer wall? Number i Unitsarrow_forward#70arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice UniversityPhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College