Concept explainers
Force on a skater’s wrist. A 52 kg ice skater spins about a vertical axis through her body with her arms horizontally outstretched, making 2.0 turns each second. The distance from one hand to the other is 1.50 m. Biometric measurements indicate that each hand typically makes up about 1.25% of body weight. (a) Draw a free-body diagram of one of her hands. (b) What horizontal force must her wrist exert on her hand? (c) Express the force in part (b) as a multiple of the weight of her hand.
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
College Physics (10th Edition)
Additional Science Textbook Solutions
Introduction to Electrodynamics
Cosmic Perspective Fundamentals
Applied Physics (11th Edition)
Lecture- Tutorials for Introductory Astronomy
College Physics: A Strategic Approach (3rd Edition)
Essential University Physics (3rd Edition)
- A "swing" ride at a carnival consists of chairs that are swung in a circle by L = 15.8 m cables attached at an angle of θ = 57.4° to a vertical rotating pole, as the drawing below shows. Suppose the total mass of a chair and its occupant is 161 kg. Calculate the tension in the cable attached to the chair.arrow_forwardA man stands on the lateral surface of a cylinder, moves his legs, and moves the cylinder with constant speed (see figure). Considering that the coefficient of friction between the shoes and the cylinder is mu = 0.3. What will be the friction force between the cylinder and the man. The mass of man m = 70 Kg.arrow_forwardTwo friends are carrying a 500 N wooden slab along a 45 degrees stairway. The slab is 1.0 m long and 0.40 m high. They each apply vertical upward force (black arrows) on the bottom edges of the box in such a way that the box remains parallel to the stairs as shown in the figure. What are the magnitudes of theforces exerted by the lower and higher friend, respectively?arrow_forward
- A teenager of mass m1=50.6kgm1=50.6kg pushes backward against the ground with his foot as he rides his skateboard towards the right. This exerts a horizontal force of magnitude Ffoot=14.2NFfoot=14.2N. The skateboard has mass m2=2.5kgm2=2.5kg. (a) Write an expression for the magnitude of the horizontal component of the force, FgroundFground, that the ground exerts on the teenager's foot. (b) In terms of given quantities, write an expression for the magnitude of the skateboard's acceleration, aa, while the teenager is pushing backwards on the ground. (c) What is the numerical value of the magnitude, in meters per squared second, of the acceleration?arrow_forwardAn Atwood machine consists of two masses hanging from the ends of a rope that passes over a pulley. The masses have the values ?1=27.0 kgm1=27.0 kg and ?2=16.0 kg.m2=16.0 kg. Assume that the rope and pulley are massless and that there is no friction in the pulley. What is the magnitude of the tension ?T in the rope?arrow_forwardThe distance between two telephone poles is d = 54.0 m. When a 1.20 kg bird lands on the telephone wire midway between the poles, the wire sags h = 0.206 m. How much tension (in N) does the bird produce in the wire? Ignore the weight of the wirearrow_forward
- Kinesiologists—scientists who study human motion—can measure the forces that act on runners as they round a curve. The forces on a runner’s feet are a vertical normal force that, on average, serves to counteract gravity, and a static friction force parallel to the ground and pointing toward the center of the runner’s circular path. The average value of this inward-pointing force is measured to be 600 N for a 75 kg runner rounding a curve that has a 2.5 m radius. What is this runner’s speed?arrow_forwardA manager walks d = 2.8 m along a uniform plank supported by the floor at one end and by a vertical rope at the other, as in the figure. Find the tension in the rope if the plank's mass and length are M = 10.7 kg and L = 7 m, the manager's mass is m = 57 kg, and the angle = 20°. T = d 0 N m Marrow_forwardA cow is pushing its baby from side of the farm to another. The floor of the farm is not frictionless. The baby has a mass of 3 kg and the cow is carefully pushing it at a constant speed of 0.5 m/s to ensure that it doesn't tip over. What is the net force acting on the baby?arrow_forward
- The physics of circular motion sets an upper limit to the speed of human walking. (If you need to go faster, your gait changes from a walk to a run.) If you take a few steps and watch what's happening, you'll see that your body pivots in circular motion over your forward foot as you bring your rear foot forward for the next step. As you do so, the normal force of the ground on your foot decreases and your body tries to "lift off" from the ground. A. A person's center of mass is very near the hips, at the top of the legs. Model a person as a particle of mass m at the top of a leg of length L. Find an expression for the person's maximum walking speed vmax Express your answer in terms of the variables L and appropriate constants. b.)Evaluate your expression for the maximum walking speed of a 70 kg person with a typical leg length of 70 cm . Give your answer in m/s. c.) Give your answer in mph.arrow_forwardThe distance between two telephone poles is d = 54.0 m. When a 1.20 kg bird lands on the telephone wire midway between the poles, the wire sags h = 0.206 m. (a) Draw a free-body diagram of the midpoint of the wire (where the bird is perched). mg O X* (b) How much tension (in N) does the bird produce in the wire? Ignore the weight of the wire. 3.15 Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. N Need Help? Read Itarrow_forwardTwo blocks of mass m, = 10 kg and mg = 5 kg are connected by a massless string that passes over a pulley as shown in the figure. The system is in static equilibrium. There is friction between m, and the inclined surface (u.-0.4), Neglect the friction between the string and the pulley. Determine the tension in the string. 10 kg 5.0 kg 37 65.35 N () 147.0 N 98.0 N 49.0 N O 52.3 Narrow_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