(20 12? Huaibei simulation), as shown in the figure, is a fitness equipment designed by the physics interest activity group of our school. It consists of a fitness equipment with a mass of m 1 and a length of 2L. Solution: Solution: Let the center of gravity of the object be at point O, as shown in the figure.

If an object is supported at point O, it can keep balance in a horizontal position.

The arm of the lever is L 1=L0-L? ①,

The moment arm L2 of the sphere = 2l-l0+r? ②,

According to the lever balance condition: F 1L 1=F2L2,

That is: m 1g(L0-L)=m2g(2L-L0+R)? ③,

Substitute ① ② into ③ to get the distance from the center of gravity point O to the terminal A of the equipment.

l0 = 2m2L+m 1L+m2rm 1+m2，

Answer: The distance from the center of gravity O to the end point A is l0 = 2m2l+m1L+m2rm1+m2.