A cylindrical bottle of oil-and-vinegar salad dressing whose volume is 1/3 vinegar (p=1.01 g/cm^3) and 2/3 oil (p=.910 g/cm^3) is at rest on a table. Initially the oil and the vinegar are separated, with the oil floating on top of the vinegar. The bottle is shaken so that the oil and vinegar mix uniformly, and the bottle is returned to the table. How has the height of the center of mass of the salad dressing changed as a result of the mixing?
a. it is higher
b. it is the same
c. not enough info
d. it is lower @Mathematics

Question

A cylindrical bottle of oil-and-vinegar salad dressing whose volume is 1/3 vinegar (p=1.01 g/cm^3) and 2/3 oil (p=.910 g/cm^3) is at rest on a table. Initially the oil and the vinegar are separated, with the oil floating on top of the vinegar. The bottle is shaken so that the oil and vinegar mix uniformly, and the bottle is returned to the table. How has the height of the center of mass of the salad dressing changed as a result of the mixing? 
a. it is higher 
b. it is the same 
c. not enough info 
d. it is lower   @Mathematics

stormfire1 · Answer

Since the vinegar is heavier than the oil and it is initially at the bottom of the container, the center of mass has to go up when you mix the bottle.  In the x direction the CM will be the same however.