question_answer

The system shown in figure 18 is in equilibrium. The maximum value of W, so that the maximum value of static frictional force on 100 kg body is 450 N, will be            

A) 100 N

B) 250 N

C) 450 N

D) 1000 N

Correct Answer: C

Solution :

[c]

For vertical equilibrium, \[{{T}_{1}}\sin {{45}^{o}}=W\]

\[\therefore \]    \[{{T}_{1}}=\frac{W}{\sin {{45}^{o}}}\]

For horizontal equilibrium,

\[{{T}_{2}}={{T}_{1}}\cos {{45}^{o}}=\frac{W}{\sin {{45}^{o}}}\cos {{45}^{o}}=W\]

and for the critical condition, \[{{T}_{2}}=F\]

\[\therefore \]      \[W={{T}_{2}}=F=450\,N\]