07_InstSolManual_PDF_Part18 - 7-18 Chapter 7 Reect Friction...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Reflect: Friction does negative work and removes mechanical energy from the system. The tension does positive work on one person and the same magnitude of negative work on the other person and therefore does no net work on the system. 7.82. Set Up: Referring to the free-body diagram, a force balance in the horizontal direction results in The force applied by the worker can thus be obtained for part (a) and used in (b) to calculate the work as For parts (c) and (d), use the normal force to calculate the nonconservative work of friction as Also apply In (e), evaluate the net work as Figure 7.82 Solve: (a) From (b) (c) (d) The normal force, n , and the gravitational force, mg , do not contribute to the work since they both act perpendi- cular to the displacement, d . (e) 7.83. Set Up: For parts (a) and (b), consider the relations and In parts (c) and (d), use Also recall that for (d). Solve: (a) Identical springs are compressed the same distance, so is the same for both springs.
Image of page 1
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