Physics

Problem

4\,\text{kg}

block is placed on a rough plane inclined at

30^{\circ}

to the horizontal. The coefficient of static friction between the block and the plane is

0.25

. What is the minimum magnitude of a force

F

applied parallel to the plane and acting upward along the plane that will keep the block at rest? Take

g = 9.8\,\text{m}\,\text{s}^{-2}

. a)

28.1\,\text{N}

11\,\text{N}

19.6\,\text{N}

14.7\,\text{N}