Question

A 6 metre long ladder weighing 40 kg leans on a frictionaless wall. Its feet rest on the floor 2m from the wall. Find the reaction forces of the wall and the floor.

Answer 1

Coefficient of friction

μ=tanϕμ=tan⁡ϕ

μ=tan15∘μ=tan⁡15∘

 

Amount of friction at contact surfaces

fA=μNA=NAtan15∘fA=μNA=NAtan⁡15∘

fB=μNB=NBtan15∘fB=μNB=NBtan⁡15∘

 

ΣFV=0ΣFV=0

NA+fB=18+72NA+fB=18+72

NA=90−fBNA=90−fB

NA=90−NBtan15∘NA=90−NBtan⁡15∘

 

ΣFH=0ΣFH=0

fA=NBfA=NB

NAtan15∘=NBNAtan⁡15∘=NB

(90−NBtan15∘)tan15∘=NB(90−NBtan⁡15∘)tan⁡15∘=NB

90tan15∘−NBtan215∘=NB90tan⁡15∘−NBtan2⁡15∘=NB

Answer 2

Explanation:

Its feet rest on the floor 1 m from the wall. Find the rection forces of the wall and the floor. ... (ii) Reaction of wall on the ladder