Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.

Coefficient of Kinetic Friction... given Spring constant?

Calculate the coefficient of kinetic friction between a 4.82 kg block and the horizontal surface on which it rests if an 82.3 N/m spring must be stretched by 2.21 cm to pull it with constant speed. Assume that the spring pulls in a direction 13.4° above the horizontal.

I have tried this problem 3 different ways, assuming that the Fk=Fs and then adding in the force in they y direction as (1-sin(theta).... I am lost

2 Answers

Relevance
  • odu83
    Lv 7
    8 years ago
    Favorite Answer

    The force of the spring

    Fs=82.3*0.0221 N

    Normal force

    N=m*g-Fs*sin13.4

    and the horizontal dynamic

    Fs*cos13.4-N*u=0 (no acceleration)

    u=Fs*cos13.4/N

    or

    u=82.3*0.0221*cos13.4/(4.82*9.81-82.3*0.0221*sin13.4)

    u=0.038

  • 5 years ago

    Please convert 2.20 Cm to 0.022 m. Spring stress = 88.2*0.022 N = a million.ninety 4 N. The spring stress works alongside the horizontal axis = a million.ninety 4 cos 14.6 N = a million.88 N. typical stress the block agains floor = 4.24*10 N = 40 2.4N. (anticipate gravity = 10 m/s²) Coefficient of kinetic friction = a million.88/40 2.4 = 0.40 4

Still have questions? Get your answers by asking now.