Concept explainers
United Nations Pendulum A large pendulum with a 200-lb gold-plated bob 12 inches in diameter is on display in the lobby of the United Nations building. The pendulum has a length of 75 ft. It is used to show the rotation of the Earth—for this reason it is referred to as a Foucault pendulum. What is the least amount of time it takes for the bob to swing from a position of maximum displacement to the equilibrium position of the pendulum? (Assume that the acceleration due to gravity is g = 9.81 m/s2 at the UN building.)
Want to see the full answer?
Check out a sample textbook solutionChapter 13 Solutions
Physics (5th Edition)
Additional Science Textbook Solutions
College Physics (10th Edition)
University Physics Volume 2
Conceptual Physical Science (6th Edition)
Lecture- Tutorials for Introductory Astronomy
Physics for Scientists and Engineers with Modern Physics
Cosmic Perspective Fundamentals
- The original “clock” used to define the length of the second was the daily rotation of Earth about its axis. Why has this clock been replaced by one based on the oscillation period of light waves emitted by atoms like cesium and rubidium?arrow_forwardA series of five 0.1-kg spheres are arrayed along a thin, lightweight rigid rod with length 0.5 m at intervals of 0,1m from one end of the rod. The system spins about an axis perpendicular to and passing through the unoccupied end of the rod with a period of 0.3 s. In this way, each mass moves in the same plane along a circular path whose radius is its distance from the rotation axis. (a) How far does each mass move during one revolution? (b) What is the speed of each mass as it orbits the axis? (c) What is the total angular momentum of the system?arrow_forwardFigure OQ7.10 shows a light extended spring exerting a force Fs to the left on a block. (i) Does the block exert a force on the spring? Choose every correct answer. (a) No, it doesnt. (b) Yes, it does, to the left. (c) Yes, it does, to the right. (d) Yes, it does, and its magnitude is larger than Fs. (e) Yes, it does, and its magnitude is equal to Fs. (ii) Does the spring exert a force on the wall? Choose your answers from (he same list (a) through (e).arrow_forward
- Reciprocating motion uses the rotation of a motor to produce linear motion up and down or back and forth. This is how a reciprocating saw operates, as shown below. If the motor rotates at 60 Hz and has a radius of 3.0 cm,estimate the maximum speed of the saw blade as it moves up and down. This design is known as a scotch yoke.arrow_forwardOne type of BB gun uses a spring-driven plunger to blow the BB from its barrel. (a) Calculate the force constant of its plunger’s spring if you must compress it 0.150 m to drive the 0.0500kg plunger to a top speed of 20.0m/s. (b) What force must be exerted to compress the spring?arrow_forwardReview. Assume a certain liquid, with density 1 230 kg/m3, exerts no friction force on spherical objects. A ball of mass 2.10 kg and radius 9.00 cm is dropped from rest into a deep tank of this liquid from a height of 3.30 m above the surface. (a) Find the speed at which the hall enters the liquid. (b) Evaluate the magnitudes of the two forces that are exerted on the ball as it moves through the liquid. (c) Explain why the ball moves down only a limited distance into the liquid and calculate this distance. (d) With what speed will the ball pop up out of the liquid? (c) How does the time interval tdown, during which the ball moves from the surface down to its lowest point, compare with the lime interval tup for the return trip between the same two points? (f) What If? Now modify the model to suppose the liquid exerts a small friction force on the ball, opposite in direction to its motion. In this case, how do the time intervals tdown and tup compare? Explain your answer with a conceptual argument rather than a numerical calculation.arrow_forward
- A piece of mud is initially at point A on the rim of a bicycle wheel of radius R rotating clockwise about a horizontal axis at a constant angular speed (Fig. P7.8). The mud dislodges from point A when the wheel diameter through A is horizontal. The mud then rises vertically and returns to point A. (a) Find a symbolic expression in terms of R, , and g for the total time the mud is in the air and returns to point .A. (b) If the wheel makes one complete resolution in the time it takes the mud to return to point A, Find an expression for the angular speed of the bicycle wheel in terms of , g, and R. Figure P7.8 Problems 8 and 69.arrow_forwardThe grandfather clock in the opening storyline depends on the period of a pendulum to keep correct time. (i) Suppose the clock is calibrated correctly and then a mischievous child slides the bob of the pendulum downward on the oscillating rod. Does the grandfather clock run (a) slow, (b) fast, or (c) correctly? (ii) Suppose a grandfather clock is calibrated correctly at sea level and is then taken to the top of a very tall mountain. Does the grandfather clock now run (a) slow, (b) fast, or (c) correctly?arrow_forwardSuppose you have a 0.750kg object on a horizontal surface connected to a spring that has a force constant of 150N/m. There is simple friction between me object and surface with a static coefficient of friction =0.100. (a) How far can the spring be stretched without moving the mass? (b) If the object is set into oscillation with an amplitude twice the distance found in part (a), and me kinetic coefficient of friction is k=0.0850, what total distance does it travel before stopping? Assume it starts at me maximum amplitude.arrow_forward
- You have to determine the acceleration due to gravity of a newly discovered planet. You have a pendulum clock that shows an accurate time on the Earth, and it is found that the same clock runs slow by a factor of 2.45 on the new planet. Describe how you can use this information to find the unknown gravitational acceleration. Make the necessary calculations and post your result. Make a new thread and complete the following about the real-world applications of this concept: You just installed a new swing in your backyard. When you are swinging, you are 168 cm from the point where you attached the swing. Calculate how long it will take for the swing to complete 4 complete cycles and post your result.arrow_forwardA pendulum, mass attached to a string, is being sung in a horizontal circle by holding on the string. The sketch shows a position of the pendulum mass when it is at the left most part of the circle when the string makes an angle θ with the vertical as shown in the sketch. (a) Draw free body diagram of the pendulum at the point so that you can use second law of motion in radial direction. (Note: It should include proper axes and components of the tension force.) (b) Write second law of motion of the ball in the radial direction and vertical directionarrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningClassical Dynamics of Particles and SystemsPhysicsISBN:9780534408961Author:Stephen T. Thornton, Jerry B. MarionPublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning