{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

HW#7 - Work and Energy

HW#7 - Work and Energy - 11.45 Model Model Paul and the mat...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
11.45. Model: Model Paul and the mat as a particle, assume the mat to be massless, use the model of kinetic friction, and apply the work-kinetic energy theorem. Visualize: We define the x -axis along the floor and the y -axis perpendicular to the floor. Solve: We need to first determine k . f Newton’s second law in the y -direction is G sin30 n T F mg n   sin30 mg T   2 (10 kg)(9.8 m/s ) (30 N)(sin30 ) 83.0 N.   Using n and the model of kinetic friction, k k f n (0.2)(83.0 N) 16.60 N. The net force on Paul and the mat is therefore net k cos30 30 N cos30 16.6 N 9.4 N F T f     . Thus, net net (9.4 N)(3.0 m) 28 J W F r The other forces G and F n make an angle of 90 with r and do zero work. We can now use the work-kinetic energy theorem to find the final velocity as follows: 2 net f i f f f net 1 0 J 2 / 2(28 J)/10 kg 2.4 m/s 2 W K K K mv v W m Assess: A speed of 2.4 m/s or 5.4 mph is reasonable for the present problem.
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
Image of page 2
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