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A cubical box ( 1m x 1m x 1m ) is filled with sand and weighs 900 N. It is desir

ID: 2246273 • Letter: A

Question

A cubical box ( 1m x 1m x 1m ) is filled with sand and weighs 900 N. It is desired to roll the

box by pushing horizontally on one of the upper edges. (a) What minimum force is required? (b)

What minimum coefficient of static friction is required? (c) Is there a more efficient way to roll

the box? If so, find the lowest possible force that would be required to be applied directly to the

box so the box will roll.

A cubical box ( 1m times 1m times 1m ) is filled with sand and weighs 900 N. It is desired to "roll" the box by pushing horizontally on one of the upper edges. (a) What minimum force is required? (b) What minimum coefficient of static friction is required? (c) Is there a more efficient way to roll the box? If so, find the lowest possible force that would be required to be applied directly to the box so the box will roll.

Explanation / Answer

let the minimu force be F let the coefficient of static friction be Uk for minimum force normal reaction N will act through the edge

then the torque balance about extreme point will be F*1= 900*0.5

since both friction and normal reaction act thorugh the point of edge their torques will be zero

therefore F = 450 N therefore in this case t

he F = force of frcition = mg*Uk Uk = F / mg = 0.5