
Answer:
a) 123.48N
b) 78.99N
Explanation:
EFy= 0 = N - W
Efxo= 0 = Fs,max - Fa
UsN - Fa
But N = mg
Substituting mg for W,in the above equation gives
Fa / Usmg
Fa= (0.31)× (42)× 9.8= 123.48N
b) Fa= (0.31)× (42-18)× 9.8
Fa= 0.31 × 26 ×9.8 = 78.99N