Concept explainers
A ladder, leaning against a wall, makes a 60° angle with the ground. When is it more likely to slip: when a person stands on the ladder near the top or near the bottom? Explain.
When is it more likely to slip: when a person stands on the ladder near the top or near the bottom?
Answer to Problem 7Q
Solution:
The ladder is more likely to slip when the person stands near the top of the ladder.
Explanation of Solution
Given info:
A ladder, leaning against a wall, makes a 60 degrees angle with the ground.
Assume that the pivot point is at the base of the ladder in contact with the ground. Then, the forces acting on the ladder with a person stand on the ladder near the top are: The weight of the ladder ( ), the weight of the person ( ), the reaction force ( )that the ground makes with the ladder, the force that the wall ( )exerts on the ladder. As the person goes up the ladder the torque ( )made by their weight also increases. The torque made by weight’s ladder is constant. Now, the ladder is in equilibrium; but when the person goes up the ladder he does torque in a clockwise direction as well as the weight of the stairs increases. If the person’s weight is much greater than the force that the wall ( )exerts on the ladder, then the ladder slides. If the person is standing at the base of the ladder then, the lever arm is zero because it goes through the pivot point, therefore there is no torque different from zero and the ladder does not slide.
Chapter 9 Solutions
Physics: Principles with Applications
Additional Science Textbook Solutions
Cosmic Perspective Fundamentals
Applications and Investigations in Earth Science (9th Edition)
Human Physiology: An Integrated Approach (8th Edition)
Campbell Biology (11th Edition)
Chemistry: An Introduction to General, Organic, and Biological Chemistry (13th Edition)
Campbell Essential Biology with Physiology (5th Edition)
- No chatgpt pls will upvotearrow_forwardCorrect answer No chatgpt pls will upvotearrow_forwardStatistical thermodynamics. The number of imaginary replicas of a system of N particlesa) cannot be greater than Avogadro's numberb) must always be greater than Avogadro's number.c) has no relation to Avogadro's number.arrow_forward
- Lab-Based Section Use the following information to answer the lab based scenario. A student performed an experiment in an attempt to determine the index of refraction of glass. The student used a laser and a protractor to measure a variety of angles of incidence and refraction through a semi-circular glass prism. The design of the experiment and the student's results are shown below. Angle of Incidence (°) Angle of Refraction (º) 20 11 30 19 40 26 50 31 60 36 70 38 2a) By hand (i.e., without using computer software), create a linear graph on graph paper using the student's data. Note: You will have to manipulate the data in order to achieve a linear function. 2b) Graphically determine the index of refraction of the semi-circular glass prism, rounding your answer to the nearest hundredth.arrow_forwardUse the following information to answer the next two questions. A laser is directed at a prism made of zircon (n = 1.92) at an incident angle of 35.0°, as shown in the diagram. 3a) Determine the critical angle of zircon. 35.0° 70° 55 55° 3b) Determine the angle of refraction when the laser beam leaves the prism.arrow_forwardUse the following information to answer the next two questions. A laser is directed at a prism made of zircon (n = 1.92) at an incident angle of 35.0°, as shown in the diagram. 3a) Determine the critical angle of zircon. 35.0° 70° 55 55° 3b) Determine the angle of refraction when the laser beam leaves the prism.arrow_forward
- No chatgpt pls will upvotearrow_forwardA beam of alpha-particles of energy 7.3MeV is used.The protons emitted at an angle of zero degree are found to have energy of 9.34MeV.Find the Q-value of this reaction .arrow_forwardAn aluminum rod and a copper rod have the same length of 100cm at 5C. At what temperatures would one of the rods be 0.5 mm longer than the other? Which rod is longer at such temperature?arrow_forward
- ROTATIONAL DYNAMICS Question 01 A solid circular cylinder and a solid spherical ball of the same mass and radius are rolling together down the same inclined. Calculate the ratio of their kinetic energy. Assume pure rolling motion Question 02 A sphere and cylinder of the same mass and radius start from ret at the same point and more down the same plane inclined at 30° to the horizontal Which body gets the bottom first and what is its acceleration b) What angle of inclination of the plane is needed to give the slower body the same acceleration Question 03 i) Define the angular velocity of a rotating body and give its SI unit A car wheel has its angular velocity changing from 2rads to 30 rads seconds. If the radius of the wheel is 400mm. calculate ii) The angular acceleration iii) The tangential linear acceleration of a point on the rim of the wheel Question 04 in 20arrow_forwardQuestion B3 Consider the following FLRW spacetime: t2 ds² = -dt² + (dx² + dy²+ dz²), t2 where t is a constant. a) State whether this universe is spatially open, closed or flat. [2 marks] b) Determine the Hubble factor H(t), and represent it in a (roughly drawn) plot as a function of time t, starting at t = 0. [3 marks] c) Taking galaxy A to be located at (x, y, z) = (0,0,0), determine the proper distance to galaxy B located at (x, y, z) = (L, 0, 0). Determine the recessional velocity of galaxy B with respect to galaxy A. d) The Friedmann equations are 2 k 8πG а 4πG + a² (p+3p). 3 a 3 [5 marks] Use these equations to determine the energy density p(t) and the pressure p(t) for the FLRW spacetime specified at the top of the page. [5 marks] e) Given the result of question B3.d, state whether the FLRW universe in question is (i) radiation-dominated, (ii) matter-dominated, (iii) cosmological-constant-dominated, or (iv) none of the previous. Justify your answer. f) [5 marks] A conformally…arrow_forwardSECTION B Answer ONLY TWO questions in Section B [Expect to use one single-sided A4 page for each Section-B sub question.] Question B1 Consider the line element where w is a constant. ds²=-dt²+e2wt dx², a) Determine the components of the metric and of the inverse metric. [2 marks] b) Determine the Christoffel symbols. [See the Appendix of this document.] [10 marks] c) Write down the geodesic equations. [5 marks] d) Show that e2wt it is a constant of geodesic motion. [4 marks] e) Solve the geodesic equations for null geodesics. [4 marks]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