a force of 20n applied parallel to the surface of a horizontal table is just sufficient to make a block of mass 4.kg move on the table caculate thd coefficient of friction between the block and the table

Answer 1

Wb = mg = 4kg * 9.8N/kg = 39.2N = Weight 0f block.

Fb = 39.2N@0deg.
Fp = 39.2sin(0) = 0 = Force parallel to surface.
Fv = 39.2cos(0) = 39.2N. = Force perpendicular to surface.

Fap - Fp - Ff = 0,
20 - 0 - Ff = 0,
Ff = 20N. = Force of friction.

u = Ff / Fv = 20 / 39.2 = 0.510. =
Coefficient of friction.