Chapter 7 Quiz Flashcards
Which of the following will improve leverage?
1) Increase force arm
2) Decrease resistance arm
3) Both A and B
4) None of the above
Both A and B
If disruption of stability is the desired outcome, which of the following should be observed?
1)
Increase base of support
2) Increase friction
3) Lower centre of mass
4) Move centre of mass to edge of base of support
Move centre of mass to edge of base of support
The perpendicular distance between the line of force and the axis defines which of the following?
1) Fulcrum
2) Moment arm
3) Torque
4) None of the above
Moment arm
The ability of a muscle to generate torque is affected by which of the following?
1) Angle of insertion
2) Cross-sectional area
3) Length of moment arm
4) All of the above
All of the above
Which of the following is a characteristic of torque?
1) It is a vector quantity.
2) It is characterized by magnitude.
3) It is characterized by direction.
4) All of the above
All of the above
The relative efficiency of a lever is proportional to which of the following?
1) Length of the force arm
2) Length of the resistance arm
3) Mechanical advantage of the lever
4) The amount of force needed to move the lever
Mechanical advantage of the lever
Which statement is true regarding moment arm?
1) Moment arm is largest when the angle of pull on a bone is 90°.
2) Changes in moment arm directly affect joint muscle torque.
3) For torque to remain constant, more force must be produced when moment arm decreases.
4) All of the above
All of the above
Why do skilled high jumpers lower their centre of mass on the last step?
1) To increase impulse at take-off
2) To increase time of support between foot and ground
3) To increase vertical velocity at take-off
4) All of the above
All of the above
A seesaw is an example of which class of lever?
1) 1st class
2) 2nd class
3) 3rd class
4) Not a lever
1st class
Which of the following does not increase stability?
1) Lower the centre of gravity
2) Decrease mass
3) Increase friction
4) Increase size of base of support
Decrease mass
In which of the following situations is maximal stability desirable?
1) A swimmer’s starting position on the blocks before a race
2) A Sumo wrestler’s crouched defensive stance
3) Maximal stability is desirable in both situations.
4) Maximal stability is desirable in neither situation.
A Sumo wrestler’s crouched defensive stance
Which of the following can increase base of support?
1) Add more points of contact (i.e. 3-point stance to 4-point stance)
2) Widen stance
3) Both A and B
4) None of the above
Both A and B
Which of the following will benefit mobility?
1) Increase mass
2) Increase friction
3) Raise centre of gravity
4) Increase base of support
Raise centre of gravity
Which of the following phrases is/are synonymous with torque?
1) Moment arm
2) Moment of force
3) Rotary force
4) Both B and C
Both B and C
The resistance arm (RA) will always be longer than the force arm (FA) in which class lever?
1) 1st class
2) 2nd class
3) 3rd class
4) None of the classes is correct.
3rd class
Which of the following is true regarding the human body’s center of gravity?
1) Always lies within the body
2) Varies from person to person, but remains constant within an individual
3) When the body is a projectile, it follows a parabolic path
4) All of the above
When the body is a projectile, it follows a parabolic path
Which of the following affects the force-generating capability of a muscle?
1) The muscle length and cross-sectional area
2) The angle and distance from the joint center of the tendon attachment to bone
3) The velocity of muscle shortening
4) All of the above
All of the above
Which of the following quantities is as important as force in the development of torque?
1) Distance from axis to line of force
2) Time
3) Type of axis
4) None of the above
Distance from axis to line of force
Torque is the angular analogue of which of the following?
1) Momentum
2) Mass
3) Force
4) Impulse
Force
In the human body, most of the lever systems formed by muscles pulling on bones are which class?
1) 2nd class
2) No particular class is dominant
3) 3rd class
4) 1st class
3rd class
A claw-tooth hammer being used to pry up a nail is an example of which class of lever?
1) 2nd class
2) Not a lever
3) 3rd class
4) 1st class
1st class
A 30 kg child sits on the right end of a see-saw 1 m from the axis. If a 20 kg child sits on the left end of the see-saw 2 m from the axis, what will happen?
1) The see-saw will balance.
2) The see-saw will tilt to the left.
3) Need more information to predict outcome
4) The see-saw will tilt to the right.
The see-saw will tilt to the left.
Which statement is true regarding postural sway?
1) It affects balance in the elderly.
2) It is reduced by widening the base of stability to a certain point.
3) It is increased by putting one foot in front of the other.
4) All of the above
All of the above
Which of the following must be true for an object to be in a state of static equilibrium?
1) The sum of all vertical forces acting on the object must be equal to zero
2) The sum of all horizontal forces acting on the object must be equal to zero
3) The sum of all torques acting on the object must be equal to zero
4) All of the above
All of the above
Third class lever systems favor which of the following?
1) Speed
2) Range of motion
3) Strength
4) Both A and B
Both A and B
Which of the following is/are true regarding center of mass?
1) In a spherical ball with evenly distributed mass, it is in the exact center
2) It is the point around which a body’s weight is equally balanced regardless of body position
3) It may be located outside an object or body
4) All of the above
All of the above
The ability to control equilibrium defines which of the following?
1) Balance
2) Mobility
3) Centre of mass
4) Stability
Balance
Which of the following is/are true regarding a force couple?
1) Created by equal forces on opposite sides of an axis
2) Created by forces acting in the same angular direction
3) Both A and B
4) None of the above
Both A and B
What will happen to the centre of mass of a human body if the arms are raised up overhead?
1) It will move up
2) It will not change
3) It will move down
4) Need more information to predict
It will move up
Which type of equipment provides constant velocity?
1) Isokinetic
2) Nautilus
3) Free weights
4) Isotonic
Isokinetic
Which of the following quantities is zero for an object in static equilibrium?
1) Momentum
2) Kinetic energy
3) Both momentum and kinetic energy
4) None of the above
Both momentum and kinetic energy
A wheelbarrow is an example of which class of lever?
1) 2nd class
2) 1st class
3) 3rd class
4) Not a lever
2nd class
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 attach to the radius at a perpendicular distance of 3 cm from the joint center at the elbow, how much force must the muscle produce?
1) 1.5 N
2) 17 N
3) 1667 N
4) 150 N
1667 N
