In the elephant exercise yard at the local zoo, there are several dung piles. A
ID: 2054173 • Letter: I
Question
In the elephant exercise yard at the local zoo, there are several dung piles. A physics student estimates that a pile at a point 3.20 m west and 7.45 m north of the southeast corner has a mass of 100 kg. The student finds another pile of estimated mass 75.0 kg at 9.00 m west and 2.30 m north of the same point, and a last pile of estimated mass 45.0 kg at 5.00 m west and 3.00 m north. What would the student find as the coordinates of the center of mass? How accurate do you think the student’s estimates are? Explain your reasoning.Hint: In each direction apply what you know about finding center of mass independently.
Explanation / Answer
Coordinate in west direction = m1l1 /m1
= 100*3.2 + 75*9 + 45*5 /(100+75+45)
= 5.545 m
Coordinate in north direction = 100*7.45 + 75*2.3 + 45*3
= 4.78 m
COM = 5.545 m west, 4.78 m north