Hall Ch.13 Test Bank Docx Equilibrium and Human Movement

Basic Biomechanics, 8e (Hall)

Chapter 13 Equilibrium and Human Movement

1) The perpendicular distance between the line of force and the axis defines what?

A) torque

B) fulcrum

C) moment arm

D) none of these answers is correct

2) Torque is the angular analogue of what?

A) momentum

B) force

C) mass

D) impulse

3) Which of the following is a characteristic of torque?

A) it is a vector quantity

B) it is characterized by magnitude

C) it is characterized by direction

D) all of these answers are correct

4) In the human body, most of the lever systems formed by muscles pulling on bones are what class?

A) 1st class

B) 2nd class

C) 3rd class

D) no particular class is dominant

5) A wheelbarrow is an example of which class of lever?

A) 1st class

B) 2nd class

C) 3rd class

D) not a lever

6) A seesaw is an example of which class of lever?

A) 1st class

B) 2nd class

C) 3rd class

D) not a lever

7) The relative efficiency of a lever is proportional to which of the following?

A) mechanical advantage of the lever

B) length of the force arm

C) length of the resistance arm

D) the amount of force needed to move the lever

8) When the elbow is extended and the elbow flexors contract, which of the component forces acts in addition to the rotary component?

A) the stabilizing component of muscle force

B) the dislocating component of muscle force

C) both the stabilizing component of muscle force and the dislocating component of muscle force

D) none of these answers is correct

9) The amount of torque which must by generated by the biceps brachii at the elbow in order to maintain the arm in a particular position is 50 Nm. If the biceps attaches to the radius at a perpendicular distance of 3 cm from the joint center at the elbow, how much force must the muscle produce?

A) 1667 N

B) 17 N

C) 150 N

D) 1.5 N

10) Which of the following affects the force-generating capability of a muscle?

A) the muscle length and cross-sectional area

B) the angle and distance from the joint center of the tendon attachment to bone

C) the velocity of muscle shortening

D) all of these answers are correct

11) Which of the following must be true for an object to be in a state of static equilibrium?

A) the sum of all vertical forces acting on the object must be equal to zero

B) the sum of all horizontal forces acting on the object must be equal to zero

C) the sum of all torques acting on the object must be equal to zero

D) all of these answers are correct

12) In analyzing the human body as a projectile, which of the following quantities follows a parabolic path?

A) the center of mass

B) the center of volume

C) the navel

D) this varies with the individual performance

13) In which of the following situations is maximal stability desirable?

A) a swimmer's starting position on the blocks before a race

B) a Sumo wrestler's crouched defensive stance

C) both a swimmer's starting position on the blocks before a race and a Sumo wrestler's crouched defensive stance

D) neither a swimmer's starting position on the blocks before a race nor a Sumo wrestler's crouched defensive stance

14) Which of the following phrases is/are synonymous with torque?

A) moment of force

B) rotary force

C) moment arm

D) both moment of force and rotary force

E) all of these answers are correct

15) Which statement is true regarding moment arm?

A) Moment arm is largest when the angle of pull on a bone is 90°.

B) Changes in moment arm directly affect joint muscle torque.

C) For torque to remain constant, more force must be produced when moment arm decreases.

D) Both moment arm is largest when the angle of pull on a bone is 90° and changes in moment arm directly affect joint muscle torque.

E) All of these answers are correct.

16) Which of the following is/are true regarding a force couple?

A) created by equal forces on opposite sides of an axis

B) created by forces acting in the same angular direction

C) both created by equal forces on opposite sides of an axis and created by forces acting in the same angular direction

D) none of these answers is correct

17) Which of the following is/are function(s) of antagonist muscles?

A) control velocity of movement

B) enhance stability of the joint

C) both control velocity of movement and enhance stability of the joint

D) none of these answers is correct

18) What is the proposed advantage of Nautilus resistance equipment over free weights?

A) resistance varies over the range of motion with Nautilus equipment

B) resistance varies over the range of motion with free weights

C) muscle force requirements change over the range of motion with Nautilus equipment

D) none of these answers is correct

19) Which type of equipment provides constant velocity?

A) Isotonic

B) Free weights

C) Nautilus

D) Isokinetic

20) Which of the following is/are true regarding dynamic equilibrium?

A) applies to bodies in motion

B) first identified by D'Alembert

C) both applies to bodies in motion and first identified by D'Alembert

D) there is no such thing as dynamic equilibrium

21) Which of the following is/are true regarding center of mass?

A) in a spherical ball with evenly distributed mass, it is in the exact center

B) it is the point around which a body's weight is equally balanced regardless of body position

C) it may be located outside an object or body

D) both in a spherical ball with evenly distributed mass, it is in the exact center and it is the point around which a body's weight is equally balanced regardless of body position

E) all of these answers are correct

22) Why do skilled high jumpers lower their COM on the last step?

A) to increase time of support between foot and ground

B) to increase vertical velocity at take-off

C) to increase impulse at take-off

D) both to increase time of support between foot and ground and to increase vertical velocity at take-off

E) all of these answers are correct

23) The ability to control equilibrium defines what?

A) stability

B) balance

C) mobility

D) center of mass

24) Which of the following can increase base of support?

A) widen stance

B) add more points of contact (i.e. 3-point stance to 4-point stance)

C) both widen stance and add more points of contact (i.e. 3-point stance to 4-point stance)

D) none of these answers is correct

25) Which one of the following incorrectly identifies the parts of a lever within the human body?

A) a bone is the rigid bar

B) a joint is the axis of rotation

C) a muscle insertion provides the point of force

D) COM of the moving segment is the point of resistance

E) all of these answers are correct

26) When net muscle torque and joint movement occur in the same direction, what type of contraction occurs?

A) concentric

B) eccentric

C) isometric

D) isotonic

27) Which of the following is as important as force in the development of torque?

A) time

B) distance from axis to line of force

C) type of axis

D) none of these answers is correct

28) The ability of a muscle to generate torque is affected by which of the following?

A) length of the moment arm

B) angle of insertion of the muscle

C) cross-sectional area of the muscle

D) all of these answers are correct

29) Choose the term that describes the rotary effect of a force.

A) stability

B) static equilibrium

C) third-class lever

D) torque

30) Choose the term that describes the perpendicular distance between a force's line of action and the axis of rotation.

A) moment arm

B) reaction board

C) second-class lever

D) segmental method

31) Choose the term that describes the pair of equal, oppositely directed forces that act on opposite sides of an axis of rotation to produce torque.

A) couple

B) D'Alembert's principle

C) first-class lever

D) fulcrum

32) Choose the term that describes a simple machine consisting of a rigid bar that may rotate around an axis.

A) first-class lever

B) second-class lever

C) lever

D) third-class lever

33) Choose the term that describes the point of support, or axis, about which a lever may rotate.

A) fulcrum

B) lever

C) mechanical advantage

D) moment arm

34) Choose the term that describes the lever positioned with the applied force and the resistance on opposite sides of the axis.

A) lever

B) second-class lever

C) first-class lever

D) third-class lever

35) Choose the term that describes the lever positioned with the applied force between the fulcrum and the resistance.

A) first-class lever

B) second-class lever

C) lever

D) third-class lever

36) Choose the term that describes the ratio of force arm to resistance arm for a given lever.

A) mechanical advantage

B) moment arm

C) reaction board

D) second-class lever

37) Choose the term that describes the point around which the weight of a body is balanced.

A) mass centroid

B) center of gravity

C) couple

D) D'Alembert's principle

38) Choose the term that describes the resistance to disruption of equilibrium.

A) stability

B) static equilibrium

C) third-class lever

D) torque

39) Torque is the product of force and the perpendicular distance from the force to the axis, also known as the ________ ________.

40) A lever positioned with the applied resistance between the axis and the force is a ________ class lever.

41) A concept indicating a balance between applied forces and inertial forces for a body in motion is called ________ ________.

42) The ability to control equilibrium defines ________.

43) The ratio of force arm to resistance arm defines ________ ________.

44) Provide 2 examples in sport, dance or rehabilitation where maximum stability is desired and explain various ways this can be accomplished.

45) Explain 1 lever system within the human body, including the lever, axis, force, resistance, class, mechanical advantage and practical advantages.

46) Discuss the factors that determine the force-generating capability of a muscle.

47) Explain the concept of net torque as it applies to a specific human movement skill.

48) Explain the importance of center of gravity (total body and segmental) as it relates to human movement. Give specific examples.

49) Running barefoot results in higher joint torque at the knee than using running shoes.

50) A motionless body is in a state of static equilibrium.

51) The center of gravity of an object is always located within the object.