Physics

Problem

4\,\text{kg}

block rests on a rough plane inclined at

30^{\circ}

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

0.40

. A horizontal force

F

is applied on the block so that its component along the plane tends to move the block up the slope. What is the least value of

F

required to start the upward motion? (Take

g = 10\,\text{m s}^{-2}

and

\cos 30^{\circ}=0.866

.) a)

60\,\text{N}

40\,\text{N}

50\,\text{N}

70\,\text{N}