76.3k views
3 votes
A 1.90-m-long barbell has a 25.0 kg weight on its left end and a 37.0 kg weight on its right end. if you ignore the weight of the bar itself, how far from the left end of the barbell is the center of gravity?

User GNOKOHEAT
by
8.8k points

2 Answers

5 votes
To solve for the distance from the left end of the barbell:37 * 1.9 = ( 37 + 25) * x x = 37*1.9 / (37+20) = 1.23333 m
Additional info: if we are going to repeat this with a uniform bar of mass 9kg whose center of mass is 0.75 m from the left, the answer would be
37 * 1.9 + 9 * 0.75 = (37 + 25+ 9) * y y = (37 *1.9 + 8 * 0.75) / (37 + 25 + 9) = 1.07 m
User Jade Cacho
by
8.5k points
3 votes

Answer: The center of gravity is 1.1338 m away from the left side of the barbell

Step-by-step explanation:

Length of the barbell = 1.90 m

The distance center of gravity from left = x

Mass on the left side = 25 kg

The distance center of gravity from right = 1.90 - x

Mass on the right side = 37 kg

At the balance point:
m_1x_1=m_2x_2


25 kg* x=37 kg* (1.90-x)


x=1.1338 m

The center of gravity is 1.1338 m away from the left side of the barbell

User Michael Niemand
by
8.4k points