Pushing shopping cart with a variable force

Pushing shopping cart with a variable force - Pushing...

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

Pushing shopping cart with a variable force Consider the same example as above, but this time, let our force change with position. Suppose that in the beginning it takes a little while (3m) for our force to get up to its maximum value, and then we get tired and push weaker over the final 3m. Now we’d like to calculate the velocity of the cart by the 10m mark. as before. Now to calculate the work done by our force, we must calculate the area under the F-x curve. This area is: and so the final velocity will be: Example: Shoving box up an inclined plane w/ friction (work done by g, f k ) Suppose we shove a 40kg box up an inclined plane at a velocity of 5m/s. If μ k = 0.25, and the angle of inclination is 20 deg, to what height will the block go before coming to rest? We will apply the work-energy equation. Let Δr be the distance the block travels up the incline. Take a minute to observe again that the work done by normal force is 0 since it is perpendicular to the motion of the block. Now from N2L, So we have, and also recognize that h = Δrsinθ, and so Δr = h/sinθ. So,
Image of page 1

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

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