Question

End A of the bar AB in figure rests on a frictionless horizontal surface and end B is hinged A horizontal force $\stackrel{F}{\to }$ of magnitude 120 N is exerted on end A. you can ignore the weight of the bar. What is the net force exerted by the bar on the hinge at B?

• A. 100 N
• B. 200 N
• C. 150 n
• D. none of these

Answer 1

The correct option is C 150 n

Using Pythagorus rule,

$4^2+x^2=5^2$

or, $x^2=5^2-4^2$

$=25-4^2$

$=25-16=9$

or, $x=3$

$\overline{F}\times x={\overline{F}}_1\times 4$

or, $120\times 3={\overline{F}}_1\times 5$

or, ${\overline{F}}_1=\frac{120\times 5}{4}=150N$