{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CH7 - What force on the string A pendulum of length 1.15 m...

Info icon This preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
A pendulum of length 1.15 m swings in a vertical plane (see figure). When the pendulum is in the two horizontal positions = 90° and = 270°, its speed is 4.00 m/s. (a) Find the magnitude of the radial acceleration and tangential acceleration for these positions. (b) Draw a vector diagram to determine the direction of the total acceleration for these two positions. c) Calculate the magnitude and direction of the total acceleration. What force on the string?
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter 7 Energy and Energy Transfer
Image of page 2
Chapter 7
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Chapter 7
Image of page 4
Introduction to Energy The concept of energy is one of the most important topics in science Every physical process that occurs in the Universe involves energy and energy transfers or transformations Energy is not easily defined
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Introduction to Energy
Image of page 6
Energy Approach to Problems The energy approach to describing motion is particularly useful when the force is not constant An approach will involve Conservation of Energy This could be extended to biological organisms, technological systems and engineering situations
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Systems A system is a small portion of the Universe We will ignore the details of the rest of the Universe A critical skill is to identify the system
Image of page 8
Valid System A valid system may be a single object or particle be a collection of objects or particles be a region of space vary in size and shape
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Problem Solving Does the problem require the system approach? What is the particular system and what is its nature? Can the problem be solved by the particle approach? The particle approach is what we have been using to this time
Image of page 10
Environment There is a system boundary around the system The boundary is an imaginary surface It does not necessarily correspond to a physical boundary The boundary divides the system from the environment The environment is the rest of the Universe
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Work The work, W , done on a system by an agent exerting a constant force on the system is the product of the magnitude, F , of the force, the magnitude r of the displacement of the point of application of the force, and cos  where is the angle between the force and the displacement vectors
Image of page 12
Work
Image of page 13

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Work, cont. W = F r cos The displacement is that of the point of application of the force A force does no work on the object if the force does not move through a displacement The work done by a force on a moving object is zero when the force applied is perpendicular to the displacement of its point of application
Image of page 14
Work Example The normal force, n, and the gravitational force, m g, do no work on the object cos = cos 90° = 0 The force F does do work on the object
Image of page 15

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
More About Work The system and the environment must be determined when dealing with work The environment does work on the system Work by the environment on
Image of page 16
Image of page 17
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern