Concept explainers
You’re choreographing your school’s annual ice show. You call for eight 60-kg skaters to join hands and skate side by side in a line extending 12 m. The skater at one end is to stop abruptly, so the line will rotate rigidly about that skater. For safety, you don’t want the fastest skater to be moving at more than 8.0 m/s. and you don’t want the force on that skater’s hand to exceed 300 N. What do you determine is the greatest speed the skaters can have before they execute their rotational maneuver?
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Essential University Physics (3rd Edition)
Additional Science Textbook Solutions
Conceptual Physics (12th Edition)
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
University Physics Volume 1
Essential University Physics: Volume 1 (3rd Edition)
Modern Physics
Physics (5th Edition)
- A figure skater has a moment of inertia of 0.45 kg-m2. He is spinning at 315.6 rpm. He extends his arms until he slows down to 68.3 rpm. What is his new moment of inerta (in kg-m2)?arrow_forwardA ride at a carnival has four spokes to which pods are attached that can hold two people. The spokes are each 15 m long and are attached to a central axis. Each spoke has mass 200.0 kg, and the pods each have mass 100.0 kg. If the ride spins at 0.2 rev/s with each pod containing two 50.0-kg children, what is the new spin rate if all the children jump off the ride?arrow_forwardA 26 kg block hangs from a 350 g rotating solid disk. The radius of the disk is 12 cm. What is the speed of the block after it has dropped 55 cm starting from rest? If a disk with radius 5.0 cm is used instead, how does your answer change?arrow_forward
- A uniform block of granite in the shape of a book has face dimensions of 20 cm and 15 cm and a thickness of 1.2 cm.The density (mass per unit volume) of granite is 2.64 g/cm3. The block rotates around an axis that is perpendicular to its face and halfway between its center and a corner. Its angular momentum about that axis is 0.104 kgm2/s.What is its rotational kinetic energy about that axis?arrow_forwardA semi-cylindrical groove of radius r = 20 cm is made on a horizontal floor. An ant wants to cross the groove. A boy decides to help the ant making a bridge consisting of straight wire segments. But all the wires available are of length l = 38 cm, so the boy rigidly connects two wires at right angle and places the bridge in the groove as shown in the figure. If the ant can crawl up a wire segment at speed v = 0.5 cm/s and down a wire segment at speed 2v, in what minimum time can the ant cross the groove with the help of this bridge?arrow_forwardA massless spring of constant k = 78.4 N/m is fixed on the left side of a level track. A block of mass m = 0.50 kg is pressed against the spring and compresses it a distance d , as in Figure P7.76. The block (initially at rest) is then released and travels toward a circular loop-the-loop of radius R = 1.5 m. The entire track and the loop-the-loop are frictionless, except for the section of track between points A and B Given that the coefficient of kinetic friction between the block and the track along AB is μk 5 0.30, and that the length of AB is 2.5 m, determine the minimum compression d of the spring that enables the block to just make it through the loop-the-loop at point C. Hint: The force exerted by the track on the block will be zero if the block barely makes it through the loop-the-loop.arrow_forward
- A turntable with a mass of 12 kg and a radius of 2 meters spins at a constant angular velocity of 140 rpm. A 500-gram scoop of uniformly-dense ice cream falls onto the turntable, so the scoop's center of mass is one meter away from the turntable's center. The scoop forms a hemisphere and has a radius of 4 cm. If there's no friction between the brick and ice cream scoop and they 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 =MR for rotation about its center of mass parallel to the z-axis. %3D Ihemisphere = MR for rotation about its center of mass parallel to the z-axis. Edit View Ansert Format Tools Table COREIarrow_forwardThree children are riding on the edge of a merry-go-round that is 162 kg, has a 1.60 m radius, and is spinning at 21.3 rpm. The children have masses of 17.4, 28.5, and 38.8 kg. If the child who has a mass of 38.8 kg moves to the center of the merry-go-round, what is the new angular velocity in rpm?arrow_forwardA horizontal circular platform rotates counterclockwise about its axis at the rate of 0.961 rad/s. You, with a mass of 66.5 kg, walk clockwise around the platform along its edge at the speed of 1.11 m/s with respect to the platform. Your 20.5 kg poodle also walks clockwise around the platform, but along a circle at half the platform's radius and at half your linear speed with respect to the platform. Your 18.3 kg mutt, on the other hand, sits still on the platform at a position that is 3/4 of the platform's radius from the center. Model the platform as a uniform disk with mass 92.9 kg and radius 1.93 m. Calculate the total angular momentum of the system.arrow_forward
- ! 9. A mass m₁ = 19.0 kg is connected by a light string that passes over a pulley of mass M = 13.0 kg to a mass m₂ = with the horizontal (see figure). There is no 6.00 kg sliding on an inclined frictionless surface that makes an angle of 24° slippage between the string and the pulley. What is the magnitude of the moment of inertia of the pulley is 1/2Mr².) m/s² Q 2 W S X ommand 28 # 3 E D C C $ A t 4 R F (1332 1332 1332 jj1332.jj13.24 V ar s % G Search or type URL 5 T G A 6 B m₂ 8 MacBook Pro Y H & N 7 jil332 eration of the system of masses? (The N m. U J 00 * 8 3 - jj1332 jj133 jj1332 jj1332 1 ← ( 9 K H 32.jj1332 jj1332 jj1332 < * O < I ) O 32 jjl332 jjl3 L command P л. 4 - : ; option M { [ + 11 21 ? = 11 e A -arrow_forwardA carnival ride tests your courage by putting you in a situation that would appear dangerous. A person with a mass of 75.3 kg steps into a cylindrical tube that has a radius of 4.1 m. The tube begins to rotate around its center axis. As the speed of rotation increases, the passenger feels pushed against the wall of the tube. When the tube is rotating rapidly, the floor drops out. Luckily, there is a coefficient of static friction between the passenger and the wall, which keeps them from falling. If the value of that coefficient is 0.501, then what is the minimum speed that the passenger must be moving at?arrow_forwardA horizontal circular platform rotates counterclockwise about its axis at the rate of 0.947 rad/s. You, with a mass of 75.1 kg, walk clockwise around the platform along its edge at the speed of 1.09 m/s with respect to the platform. Your 20.3 kg poodle also walks clockwise around the platform, but along a circle at half the platform's radius and at half your linear speed with respect to the platform. Your 18.9 kg mutt, on the other hand, sits still on the platform at a position that is 3/4 of the platform's radius from the center. Model the platform as a uniform disk with mass 92.7 kg and radius 1.95 m. Calculate the total angular momentum of the system. total angular momentum: kg · m?/sarrow_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