A coolie uses a sloping wooden plank of length $2.0 m$ to push up a drum of mass $100 k g$ into the truck at a height $1.0 m .$
(a) What is the mechanical advantage of the sloping plank ?
(b) How much effort is needed to push the drum up into the truck ?
What assumption have you made in arriving at the answer in part (b) above ?

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Solution

Length of sloping wooden plank $l = 2.0 m$
Load $= 100 k g f$
Height of inclined plane $h = 1 m$
(a) The mechanical advantage of the sloping plank
$M . A . = \frac{l}{h} = \frac{2}{1} = 2$
(b) Effort needed to push the drum up into the truck =
$E f f o r t = \frac{L o a d}{M . A .} = \frac{100}{2} = 50 k g f$
Assumption: There is no friction between the drum and the plank.

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Length of sloping wooden plank l=2.0mLoad =100kgfHeight of inclined plane h=1m(a) The mechanical advantage of the sloping plankM.A.=lh=21=2(b) Effort needed to push the drum up into the truck = Effort=LoadM.A.=1002=50kgfAssumption: There is no friction between the drum and the plank.