Answer:
the girl must sit 2 cm from the pivot at the opposite end of the seesaw.
Explanation:
Given;
length of the seesaw, L = 4.0 m
weight of the boy, W₁ = 400 N
position of the boy from the pivot, d₁ = 1.5 m
weight of her sister, W₂ = 300 N
First, make a sketch of this information given;
0---0.5m---------------------Δ--------------------------4m
↓<--------1.5m-------> <---------x--------->↓
400 N 300N
Apply the principle of moment about the pivot, to determine the value of x;
Sum of anticlockwise moment = sum of clockwise moment
400(1.5) = 300(x)
600 = 300x
x = 600/300
x = 2 cm
Thus, the girl must sit 2 cm from the pivot at the opposite end of the seesaw.
