Answer:
1/3 the distance from the fulcrum
Explanation:
On a balanced seesaw, the torques around the fulcrum calculated on one side and on another side must be equal. This means that:
[tex]W_1 d_1 = W_2 d_2[/tex]
where
W1 is the weight of the boy
d1 is its distance from the fulcrum
W2 is the weight of his partner
d2 is the distance of the partner from the fulcrum
In this problem, we know that the boy is three times as heavy as his partner, so
[tex]W_1 = 3 W_2[/tex]
If we substitute this into the equation, we find:
[tex](3 W_2) d_1 = W_2 d_2[/tex]
and by simplifying:
[tex]3 d_1 = d_2\\d_1 = \frac{1}{3}d_2[/tex]
which means that the boy sits at 1/3 the distance from the fulcrum.
