Answer :
Answer:
[tex]f = 50\,N[/tex]
Explanation:
Let assume that floor is horizontal. By definition, the force of friction is less or equal to the maximum static friction force. That is to say:
[tex]f \leq \mu_{s}\cdot m \cdot g[/tex]
The maximum friction force is:
[tex]f_{max} = 0.35\cdot (20\,kg)\cdot (9.807\,\frac{m}{s^{2}} )[/tex]
[tex]f_{max} = 68.67\,N[/tex]
By applying Newton's law, the box has the following physical model:
[tex]\Sigma F = F - f = 0[/tex]
Where:
[tex]f = F[/tex]
Real friction is equal to 50 N, which is less than maximum friction force. Therefore, the static friction on the box is:
[tex]f = 50\,N[/tex]