Deck 2: Mechanical Principles: Kinetics

Question 1

A person being propelled in a wheelchair is an example of _____________ equilibrium.

A) static
B) dynamic
C) neutral
D) stable

Answer 1

neutral

Question 2

According to Newton's First Law of Motion:

A) Acceleration is directly proportional to the net force applied to a body.
B) Acceleration is inversely proportional to the mass of the moving object.
C) A body at rest will remain at rest.
D) For every action, there is an equal and opposite reaction.

Answer 2

A body at rest will remain at rest.

Question 3

If excessive, this source of force may retard joint motion:

A) gravity
B) muscular
C) externally applied resistance
D) friction

Answer 3

friction

Question 4

If insufficient, this source of force may promote instability:

A) gravity
B) muscular
C) externally applied resistance
D) friction

Question 5

Your patient is performing shoulder flexion from 0 to 180 $\degree$ in a standing position with his elbow extended while holding a 5-pound weight in his hand. The torque imposed by the 5-pound weight is greatest at ______ $\degree$ .

A) 0
B) 45
C) 90
D) 135
E) 180

Question 6

Your patient is having difficulty performing shoulder abduction from 0 to 90 $\degree$ with a cuff weight around his forearm while sitting in a chair. To make the exercise as easy as possible you recommend that he or she move the cuff weight ____________ and perform the activity in a _________ position.

A) further distal; side-lying
B) more proximal; side-lying
C) further distal; standing
D) more proximal; standing

Question 7

Motion that occurs about the x-axis takes place in the ____________ plane.

A) sagittal
B) frontal
C) coronal
D) transverse

Question 8

The center of gravity of a body is:

A) the theoretical point around which the mass of the object is balanced
B) easier to find in asymmetrical objects than it is in symmetrical objects
C) the point of origin for gravity's vector force
D) A and C
E) All of the above

Question 9

Assuming a right triangle, to calculate the cosine of theta one should:

A) divide the opposite side by the hypotenuse
B) divide the adjacent side by the hypotenuse
C) divide the adjacent side by the opposite side
D) divide the hypotenuse by the adjacent side

Question 10

The "normal" force vector is primarily responsible for producing:

A) compression
B) distraction
C) rotation
D) tangential motion

Question 11

The center of gravity of the adult body in the anatomic position is:

A) anterior to the border of the 11th thoracic vertebra
B) anterior to second sacral vertebra
C) just below the xiphoid process of the sternum
D) just above the knee joint

Question 12

Related to first class lever systems, which of the following is most accurate?

A) The point of resistance application lies between the force and the axis.
B) They are the most common lever system in the human body.
C) They exhibit a force advantage so large weights can be supported or moved by a smaller force.
D) The axis of rotation is located between the force and resistance arms.

Question 13

Theoretically as it relates to lever arms, sit-ups are most difficult when the arms are positioned __________ of the individual.

A) at the side
B) on the stomach
C) across the chest
D) clasped behind the head

Question 14

Motion that occurs about the y-axis takes place in the ___________ plane.

A) sagittal
B) frontal
C) coronal
D) transverse

Question 15

The perpendicular distance from the force vector to a joint's axis of motion is referred to as the:

A) moment
B) lever arm
C) moment arm
D) torque

Question 16

Archimedes' principle states that a body submerged in a liquid is buoyed up by a force ___________ the weight of the liquid displaced.

A) less than
B) equal to
C) greater than
D) two times

Question 17

The z-axis may also be referred to as the _____________ axis.

A) anterior-posterior
B) medial-lateral
C) superior-inferior
D) vertical

Question 18

To reduce the effect of weight on a joint a clinician could:

A) have the patient perform movements of the affected joint parallel to the Earth
B) incorporate the use of a sling
C) encourage the use of crutches
D) recommend aquatic therapy
E) All of the above

Question 19

Velocity of rotary motion is best expressed in:

A) meters/second
B) meters/second²
C) feet/second
D) degrees/second

Question 20

According to Newton's Second Law of Motion:

A) Acceleration is directly proportional to the net force applied to a body.
B) Acceleration is directly proportional to the mass of the moving object.
C) A body at rest will remain at rest.
D) For every action, there is an equal and opposite reaction.

Question 21

Which of the following represents the least degree of stability?

A) high center of gravity; large base of support
B) low center of gravity; large base of support
C) high center of gravity; small base of support
D) low center of gravity; small base of support

Question 22

A torque's greatest magnitude occurs when the direction of application is at a right angle or 90 $\degree$ to the segment or extremity.

Question 23

When a body part is positioned and supported to move in a plane perpendicular to the earth, the effects of gravity are reduced so a muscle weaker than 3/5 is able to move a segment.

Question 24

A body is stable when the line of gravity runs __________the center of its base of support.

A) above
B) next to
C) through
D) below

Question 25

Using crutches ______________ an individual's base of support.

A) increases
B) decreases
C) does not alter
D) negatively influences

Question 26

Small forces imparted to the distal aspect of an extremity (i.e., ankle) create large torques to the proximal joints (i.e., hip).

Question 27

In athletics, a large base of support is always advantageous.

Question 28

The resultant force is the simplest force that produces the same effect as all the forces acting together.

Question 29

If a torque produces or tends to produce a counterclockwise motion of the coordinate system, the sign is positive.

Question 30

Your patient had an above knee amputation on the left. In which direction did the patient's center of gravity shift?

A) Up and to the right
B) Down and to the right
C) Up and to the left
D) Down and to the left

Question 31

Vector forces can be combined when more than one force is applied to a body or segment.

Question 32

The terms, "weight" and "mass" are defined the same and may be used interchangeably.

Question 33

The center of gravity rises when an individual elevates his or her arms overhead.

Question 34

Muscles can only produce force on their bony segments when they contract.

Question 35

The direction of gravity is always going to be a vertically downward pull from the center of mass toward the center of the earth.

Question 36

When the body or a body segment moves over a surface, friction also is a torque that affects movement.

Question 37

Whenever the force arm of the muscle working is shorter than the resistance arm of the segment moved by the muscle, the muscle must exert less force to lift the segment.

Question 38

Force is bidirectional and torque is unidirectional.

Question 39

Most levers in the body are classified as ___________ class levers.

A) first
B) second
C) third
D) fourth

Question 40

Third class levers, although mechanically inefficient, offer the benefit of a large excursion in range of motion with little or small changes in muscle length.