Mechanics again and again.... (f=ur)
Two lights strings are attached to a block of mass 20kg. The block is in equ on a horizontal surface ab with the strings taut. Diagram below
Given surface is smooth find value of T and magnitude of contact force..
2 the surface is rough and block is on the point of slipping. The frictional force has magnitude 25N and acts towards A. Find coeefficient of friction between block and the surface...
First part was easy.... I equated the x component of both side and it gave me the value of 130
and using that value, I worked the y component that gave me 150,
200 - 150 = 50 N for the contact force....
Second part, i am confused, f = uR
F would be 25 ?
R = the resultant aka 50 ?
but i cant get the answer right, its supposed to be 0.268N
P.s some explanation how to work these cases would help me greatly..