Chapter 7 Quiz

Question 1

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

Answer 1

Both A and B

Question 2

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

Answer 2

Move centre of mass to edge of base of support

Question 3

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

Answer 3

Moment arm

Question 4

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

Answer 4

All of the above

Question 5

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

Answer 5

All of the above

Question 6

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

Answer 6

Mechanical advantage of the lever

Question 7

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

Answer 7

All of the above

Question 8

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

Answer 8

All of the above

Question 9

A seesaw is an example of which class of lever?

1) 1st class
2) 2nd class
3) 3rd class
4) Not a lever

Answer 9

1st class

Question 10

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

Answer 10

Decrease mass

Question 11

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.

Answer 11

A Sumo wrestler’s crouched defensive stance

Question 12

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

Answer 12

Both A and B

Question 13

Which of the following will benefit mobility?

1) Increase mass
2) Increase friction
3) Raise centre of gravity
4) Increase base of support

Answer 13

Raise centre of gravity

Question 14

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

Answer 14

Both B and C

Question 15

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.

Answer 15

3rd class

Question 16

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

Answer 16

When the body is a projectile, it follows a parabolic path

Question 17

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

Answer 17

All of the above

Question 18

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

Answer 18

Distance from axis to line of force

Question 19

Torque is the angular analogue of which of the following?

1) Momentum

2) Mass

3) Force

4) Impulse

Answer 19

Force

Question 20

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

Answer 20

3rd class

Question 21

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

Answer 21

1st class

Question 22

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.

Answer 22

The see-saw will tilt to the left.

Question 23

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

Answer 23

All of the above

Question 24

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

Answer 24

All of the above

Question 25

Third class lever systems favor which of the following?

1) Speed

2) Range of motion

3) Strength

4) Both A and B

Answer 25

Both A and B

Question 26

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

Answer 26

All of the above

Question 27

The ability to control equilibrium defines which of the following?

1) Balance

2) Mobility

3) Centre of mass

4) Stability

Answer 27

Balance

Question 28

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

Answer 28

Both A and B

Question 29

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

Answer 29

It will move up

Question 30

Which type of equipment provides constant velocity?

1) Isokinetic

2) Nautilus

3) Free weights

4) Isotonic

Answer 30

Isokinetic

Question 31

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

Answer 31

Both momentum and kinetic energy

Question 32

A wheelbarrow is an example of which class of lever?

1) 2nd class

2) 1st class

3) 3rd class

4) Not a lever

Answer 32

2nd class

Question 33

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

Answer 33

1667 N