Answer:
the center of gravity moves by 1.9 m towards the origin
Explanation:
from the question we are given the following
John's mass (Mj) = 91.2 kg
Barbara's mass (Mb) = 51.9 kg
John's location (Xj) = + 9.99 m
Barbara's location (Xb) = +3.27 m
center of mass (X) = ?
the center of mass is where the masses of John and Barbara is concentrated, and it is given by the formula below
X = ( ( Mj x Xj ) + ( Mb x Xb ) ) / (Mj + Mb)
X = ( ( 91.2 x 9.99 ) + ( 51.9 x 3.27 ) ) / ( 91.2 + 51.9 )
X = 7.6 m
now when they switch positions their locations now become
John's location (Xj) = + 3.27 m
Barbara's location (Xb) = +9.99 m
now putting their new locations into the formula
X = ( ( 91.2 x 3.27 ) + ( 51.9 x 9.99 ) ) / ( 91.2 + 51.9 )
X = 5.7 m
therefore the center of mass moves by
7.6 - 5.7 = 1.9 m
the center of gravity moves by 1.9 m towards the origin