Question

QUESTION 

What would happen if a support is placed exactly at x = 79 cm followed by the removal of the supports at the subject's head and feet? (Assume the board is removed along with the supports. Select all that apply.) 

 The subject would remain balanced.

 The subject's center of gravity would shift toward his feet. 

 The subject's center of gravity would not shift.

 The subject's feet would sink toward the ground. 

 The subject's center of gravity would shift toward his head.

 The subject's head would sink toward the ground.

PRACTICE IT 

Use the worked example above to help you solve this problem. In this example, we show how to find the location of a person's center of gravity. Suppose your lab partner has a height L of 175 cm (5 ft. 9 in) and a weight w of 772 N (174 lb). You can determine the position of his center of gravity by having him stretch out on a uniform board supported at one end by a scale, as shown in the figure. If the board's weight wb is 53 N and the scale reading F is 3.24 x 10²N, find the distance of your lab partner's center of gravity from the left end of the board. 

EXERCISE 

Suppose a 431-kg alligator of length 3.3 m is stretched out on a board of the same length weighing 91 N. If the board is supported on the ends as shown in the figure, and the scale reads 1,985 N, find the x- component of the alligator's center of gravity. (Let x = 0 correspond to the left end of the board.)

Answer 1