Answer:
Weight needed to balance the bar is [tex]8.5N[/tex]
Explanation:
Given the weight of the bar is [tex]8N[/tex]
The length of the bar is [tex]5m[/tex]
The weight of the bar will be uniformly distributed over the entire span. We will consider this as a point load acting in the middle of span length, which is at a distance of [tex]2.5m[/tex] from both ends.
Now applying momentum equation about balanced load we get, (see attachment)
[tex]\sum m_i=0\\2(m)+8(1)-8(0.5)-7(3)=0\\2m+8-4-21=0\\2m-17=0\\2m=17\\m=\frac{17}{2}=8.5\\So,\ m=8.5N[/tex]
