Physics

posted by .

A small box is held in place against a rough vertical wall by someone pushing on it with a force directed upward at 28degrees above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.40 and 0.30, respectively. The box slides down unless the applied force has magnitude 18 N.

What is the mass of the box in kilograms?

  • Physics -

    1. Find Fn
    Fn=18N*cos(28)=15.9N

    2. Find Forces in Y direction to solve for m
    18N*sin(28)+Fn*fs
    18N*sin(28)+(15.9N*0.4)-9.8m=0

    Ans: m=1.5kg

  • Physics -

    where did you get the 0.4??

  • Physics -

    That's the static coefficient of friction for the surface

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. University Physics

    A small box is held in place against a rough vertical wall by someone pushing on it with a force directed upward at 28degrees above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.40 and …
  2. physics

    a force F pushes on a box of mass m that initially is at rest on a rough, horizontal surface. the force F is directed at an angle theta = 30 degreees above the horizontal. the coefficants of friction between the plane and the box are …
  3. Physics

    A box is held against a wall (not resting on the ground). What minimum horizontal force will JUST prevent the 5.0kg box from sliding if the coefficient of friction betweent he wall and the box is 0.65?
  4. physics

    A box is being lowered down a wall at constant speed by a girl, as shown. Her hand is pushing on the edge of the box with 50 N of force at a 45◦ angle with respect to the horizontal. The box weighs 40 N. Find the coefficient …
  5. physics

    A box is being lowered down a wall at constant speed by a girl, as shown. Her hand is pushing on the edge of the box with 50 N of force at a 45◦ angle with respect to the horizontal. The box weighs 40 N. Find the coefficient …
  6. Physics

    he weight of the block in the drawing is 77.0 N. The coefficient of static friction between the block and the vertical wall is 0.490. (a) What minimum magnitude of the force is required to prevent the block from sliding down the wall?
  7. Physics

    A small box is held in place against a rough wall by someone pushing on it with a force directed upward at 29.8° above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.400 and 0.320, respectively. …
  8. Physics

    A small box is held in place against a rough wall by someone pushing on it with a force directed upward at 29.8° above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.400 and 0.320, respectively. …
  9. Physics

    A small box is held in place against a rough vertical wall by someone pushing on it with a force directed upward at 28∘ above the horizontal. The coefficients of static and kinetic friction between the box and wall are 0.40 and …
  10. Physics - Forces

    A 10 kg block is pressed against a vertical wall and held in place by a force F of 180 N, 37° above the horizontal. The coefficient of static friction μS=0.20. Find the magnitude and direction of the frictional force. The answer …

More Similar Questions