posted by Kyle .
You are holding a shopping basket at the grocery store with two 0.69-kg cartons of cereal at the left end of the basket. The basket is 0.90 m long. Where should you place a 1.8-kg half gallon of milk, relative to the left end of the basket, so that the center of mass of your groceries is at the center of the basket?
The sum of the moments about the center of the basket must be zero. That means the moment due to the cereal boxes and the moment due to the milk must be equal and opposite.
"Moment" means weight (or mass) multiplied by the lever arm.
2*0.69*0.45 = 1.8 * X
Solve for X, which is the distance of the milk, measured to the right of center