A steel block is resting on a Flat plank 6m long ,and how high can one end of a plank be lifted For the block to start to move,if the coeficient of friction is 0.3

2 answers

I feel like the weight of the steel block has to be given in order to solve this problem…
Fp = mg*sin A = Force parallel to the
incline.

Fn = mg*Cos A = Normal = Force perpendicular to the incline.

Fs = u*Fn = Force of static friction.

Fp-Fs = 0
Fp = Fs
mg*sin A = u*mg*Cos A
Divide both sides by mg*Cos A:
sin A/Cos A = u = 0.3
sin A/Cos A = Tan A
Tan A = 0.30
A = 16.7o

h = L*sin16.7 = 6*sin16.7 = 1.72 m.