Deck 14: The Center of Gravity and Stability

Question 1

Which of the following must be true in order for a state of equilibrium to exist?

A) all linear forces acting on the object must be balanced, torques may be unbalanced
B) all torques acting on the object must be balanced, linear forces may be unbalanced
C) neither torques nor linear forces acting on the object must equal zero
D) the sum of all forces and torques acting on the object must equal zero

Answer 1

the sum of all forces and torques acting on the object must equal zero

Question 2

Which of the following defines the line of gravity of the body?

A) intersection of cardinal sagittal & frontal planes
B) vertical line bisecting the body laterally
C) intersection of cardinal sagittal & frontal planes AND vertical line passing through center of gravity
D) intersection of cardinal sagittal & horizontal planes AND vertical line bisecting the body laterally

Answer 2

intersection of cardinal sagittal & frontal planes AND vertical line passing through center of gravity

Question 3

Which of the following defines the center of gravity of the body?

A) intersection of cardinal sagittal and frontal planes
B) intersection of cardinal frontal and horizontal planes
C) intersection of cardinal sagittal and horizontal planes
D) intersection of all 3 cardinal planes

Answer 3

intersection of all 3 cardinal planes

Question 4

What does the center of gravity of an object represent?

A) exact center anatomically
B) geometric center
C) center of mass of body
D) center of the base of support

Question 5

Which of the following methods would be the most appropriate to use when locating the center of gravity of the body on a film tracing?

A) segmental method
B) reaction board method
C) vector resultant method
D) pendulum method
Short Answer Questions

Question 6

Which of the following positions would be the most stable?

A) leaning on crutches with the weight centered equally between crutches and feet
B) crouched on all fours with the weight over the hands and the hips elevated
C) a forward/backward stride position
D) standing erect with one foot on a bench

Question 7

What might you do to help you maintain your balance if you were suddenly pushed hard from behind?
Justify your answers.

Question 8

To take a step one must become ____ and then ____ so you move from one place to another.

A) stable, unstable
B) unstable, vertical
C) unstable, stable
D) stable, horizontal

Question 9

An individual is expecting to be pushed from the left side. What would be the best standing position to assume in order to absorb the force without losing one's balance?

A) forward-backward stride stance, line of gravity toward left edge of base of support
B) forward-backward stride, line of gravity in center of base of support
C) side stride stance, line of gravity towards left edge of base of support
D) side stride stance, line of gravity toward right edge of base of support

Question 10

How might one adjust ones stance to increase stability in the following situations?
standing on the deck of a boat
standing on a bus which starts and stops suddenly
preparing to move in an unknown direction

Question 11

Why is it difficult (impossible) to bend over and touch one's toes with the heels and the buttocks against a wall?

Question 12

Explain the limitations that exist on how far the base of support can be widened in a standing position.

Question 13

What is the primary factor affecting the stability of an object?

A) height of object
B) location of center of gravity
C) mass of object
D) size and weight of object

Question 14

Name three things a basketball player might do in order to go from a stationary position to a fast run very quickly.

Question 15

What might an athlete do in order to move straight forward quickly?
1) rise up on the toes
2) shift the weight back
3) lift one foot off the ground
4) lean forward
5) drop lower to the ground

A) 1, 2, 3
B) 1, 3, 4
C) 2, 3, 5
D) 2, 4, 5