An 80 -lb and a 100-lb child are balancing a seasaw. The 80-lb child is 5ft from the fulcrum. How far from the fulcrum is the child 100 l-lb?

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Answer 1 · 2018-05-18T13:04:23

#4# feet

For a balanced lever (seesaw), the moments are equal on both sides.

So, we use the equation:

#m_1d_1=m_2d_2#

where:

#m_1,m_2# are the masses of the two objects

#d_1,d_2# are the distances of the two objects from the fulcrum

Then, we get:

#80 \ "lbs"*5 \ "ft"=100 \ "lbs"*d_2#

#d_2=(80color(red)cancelcolor(black)"lbs"*5 \ "ft")/(100color(red)cancelcolor(black)"lbs")#

#=4 \ "ft"#