KNH 381 Final Study (all quizzes and practice exams)
Which statement is false?
- Force is required to maintain a constant state of motion TRUE STATEMENTS: - Motion can exists without an applied force present - An external force is necessary to change a system's motion - An internal force can change the shape of the system
The _________ of projectile motion remains constant during flight time assuming there is no dynamic fluid force.
- Horizontal acceleration - Horizontal velocity
Qualitative motion analysis:
- Is subjective - Is practical
Kinematics involves the description of what 2 characteristics of motion?
- Spatial - Temporal
The center of gravity of a displaced volume of water is:
- The center of buoyancy - The axis of rotation of a floating person
The kinetic friction force between a box and a wooden flood depends on all of the following except:
- The net force applied to move the box KINETIC FRICTION FORCE DOES DEPEND ON: - the surface texture of the box - the surface texture of the floor - the mass of the box
What are the functions of a machine?
- Transmit a force from one place to another - Increase the magnitude of a force - Increase the linear distance and velocity of a force - Change the direction of a force
In general, a suspended object will come to rotational equilibrium in a position in which the center of gravity is:
- at the lowest point possible - directly under the base of support
Which statements about the anteroposterior axis are true?
- it runs horizontally from front to back - it's perpendicular to the frontal plane NOT: - it's the axis around which a forward roll is performed
Compared to the cartesian coordinate system, the polar coordinate system has the advantage of being able to describe:
- vectors - segments
A torque that causes counterclockwise rotation is assigned a _________ value.
Positive
The __________ angle is formed by the intersection of a line from the anterior superior iliac spine of the pelvis and the center of the patella and a line from the center of the patella to the tibial tuberosity.
Q angle
An engine may turn at a certain number of revolutions per minute, or rpm. RPM is a measure of:
angular speed
What is the name of the discipline that studies measurements of the body and body segments?
anthropometry
A person using a wheel barrow is an example of a:
2nd class lever system
How many DOF does 2D planer motion have?
3
Which class of lever system has the motive force between the resistive force and the fulcrum?
3rd class
Each myosin filament is surrounded by _________ actin filaments.
6
What vector would have the largest horizontal force component?
A force of 600 N applied to a ball at an angle of 45 degrees from the horizontal +X
Metabolic systems provide energy for muscle contraction in the form of:
ATP
Rigor mortis is muscle stiffness cause by the inability to detach myosin cross-bridges because of the lack of available _________ after death.
ATP
Which term describes motion in the frontal plane around the anteroposterior axis that moves a segment away from anatomical position?
Abduction
During the swing phase of running gait, the hip flexors act to flex the hip. What is the role of the hamstrings during the swing phase of running gait at the hip joint?
Antagonist
Frontal plane motion occurs around the _______ axis.
Anteroposterior axis
Why does lowering the center of gravity increase rotational stability?
Because the enter of gravity must be lifted more to disrupt equilibirum
A force having a line of action that passes through an object's center of mass is called a __________ force
Centric NOT: - moment - angular - torque - eccentric
What will decrease rotational stability of a standing human?
Decreasing the size of base of support NOT: - lowering the center of gravity - increasing mass - keeping the center of gravity (line of force) in the middle of the base of support
The relationship of an object's mass relative to it's volume is called:
Density NOT: - pressure - lift/drag ratio - viscosity - weight
When the line of action of gravitational force moves outside the base of support, gravity becomes a:
Disruptive torque producer
If 2 objects collide and bounce off each other, the collision is called:
Elastic
What is one component that contributes to the parallel elastic component of skeletal muscle?
Epimysium
Which discipline is concerned with the factors that influence the interaction of humans and machines?
Ergonomics
The summation of speed principle:
Explains the advantage of using an open kinetic chain for the production fo projectile motion.
________ returns the body segment to the anatomical position in the sagittal plane around the mediolateral axis.
Extension
(T/F) 8 four-year-old children should be understood mechanically as miniature, scaled-down adults.
False
(T/F) A global reference frame has an origin on a specific body segment and moves with that body segment, whereas a local reference frame is fixed in the environment.
False
(T/F) At the olympic games in Mexico City in 1968, American Bob Beamon broke the world record for the long jump by an amazing 55cm.
False
(T/F) Bernoulli's principle states that a body submerged in a fluid will be buoyed up by a force that is equal in magnitude to the weight of the displaced fluid.
False
(T/F) Body Fat% is positivelly correlated with BMI, but more strongly in men than in women.
False
(T/F) Buoyant force increases as immersion depth increases.
False
(T/F) For any given motion of a body, its linear distance traveled will never exceed its linear displacement.
False
(T/F) If system acceleration equals zero, the system must be stationary.
False
(T/F) Lift is an example of buoyant force
False
(T/F) Motor development is the discipline that describes how the nervous system controls skilled motor performance
False
(T/F) Vector chaining is a form of trigonometric vector analysis
False
(T/F) A person described as linear and relatively thin for their height would be considered strongly endomorphic.
False (ectomorph)
What statement best describes negative acceleration?
Final velocity<initial velocity
Turbulent flow is an important factor in:
Form drag
Each bundle of muscle fibers (fascicle) is held together by a layer of connective tissue called:
Perimysium
____________ refer to preferred states of the system given its current architecture and previous history of activity.
Intrinsic Dynamics
What do we call the study of forces that inhibit, cause, facilitate, or modify the motion of a body?
Kinetics
___________ is the product of an applied force and the time interval of force application.
Linear impulse
Which contributes more to rotational inertia, mass or mass distribution?
Mass distribution
The perpendicular distance between the axis of rotation and the line of action of force is called the:
Moment arm or force arm
A system's quantity of motion is called:
Momentum NOT: - acceleration - displacement - velocity - peak rate of motion
What happens at the short end of the muscle length-tension relationship graph?
Muscle tension decreases because filament overlap prevents optimal cross-bridge activity
Runner A increases her velocity from 6.5 m/s to 9.8 m/s, and runner B increases her velocity from 4.2 m/s to 7.9 m/s. Who has the higher acceleration.
Need more information because the time interval is required to measure acceleration
A cup of coffee sits in the cup holder of a moving car. Which of Newton's laws best explains why the coffee sloshes forward when the car slows rapidly?
Newton's First law
Which of Newton's Laws explains the principle of ground reaction forces measured in biomechanics laboratories when a person stands on or walks over a force platform in the floor?
Newton's Third law
What type of movements happen so quickly that the CNS doesn't have time to detect and use feedback to modify the movement?
Open-loop movements
In a polar coordinate system, the location of a given point is defined by its distance (radius) r from the __________ and by the angle between the chosen reference axis and the line representing r.
Origin
A tendon that has been stretched but does not return to its original resting length when tensile stress is removed has encountered stresses in the _______________ region of the stress-strain curve
Plastic region
What is the primary purpose of increasing knee flexion in the non-support leg when increasing running speed?
Reducing the rotational inertia of the leg
The pythagorean theorem is an expression of ratios between the lengths and sides of a:
Right triangle
Which cardinal plane divides the human body in half along the midline into right and left masses?
Sagittal
Which of the following has the highest specific gravity? - Water - Salt water - vegetable oil - air - helium
Salt water
What is not one of the five unique properties of a force vector?
Subjectivity THESE ARE: 1. Direction 2. Orientation 3. Magnitude 4. Point of application 5. Line of action
Any structure or organization of related structures whose state of motion is of analytical interest is called a(n):
System
Considering the right arm, what would the most proximal point be?
The midpoint of the humerus bone (the point closest to the midline of the body)
Which approach to qualitative motion analysis is most likely to view the body in component sections?
The component approach NOT: - the global approach - the graphical approach - the composite approach - the total body approach
The development of a mature throwing pattern by children involves increasing throw impulse by increasing:
The duration of the force application
In a first class lever system, when the fulcrum is moved closer to the motive force:
The moment arm for the resistive force becomes longer, and the resistive force gains a mechanical advantage.
What point on a rotating segment will experience the greatest tangential linear velocity?
The most distal point
Definition of the term 'moment arm' (aka force arm)?
The perpendicular distance between the axis of rotation and the line of action of the applied force
Considering the principle of conservation of angular momentum, what happens to a spinning figure skater if their moment of inertia increases?
The skater will spin slower
What is the angular analog of the sum of F = ma?
The sum of T = Ia
What kind of spin would a volleyball player impart on the ball in order to minimize flight time?
Top spin
__________ is defined as the tendency of an eccentric force to rotate an object around an axis.
Torque
(T/F) A dumbbell curl performed by a standing person with their right arm would be considered an open kinetic chain motion.
True
(T/F) Eccentric muscle contractions can generate greater tension than concentric contractions.
True
(T/F) It is possible to perform vector composition with four force vectors using graphical vector analysis.
True
(T/F) Lift force can act in any direction in 3D space.
True
(T/F) The center of mass of a system is located at the intersection of all three cardinal planes.
True
(T/F) the distance from the shoulder to the elbow during horizontal adduction (at the shoulder) could be considered a "radius of rotation".
True
Which of the following is an example of a tool that constitutes a 3rd class lever? - tweezers - scissors - hammer to remove a nail - pliers - screwdriver to open a paint can
Tweezers
A 12 N force vector points up and tot he right, forming a 45 degree angle with the +X axis. Another 12N vector points up and tot he left, forming an angle of 45 degrees with the -X axis. What is the direction of the resultant of these 2 vectors?
Upward
A proportional change in __________ will have the largest influence on drag force.
Velocity
The ________ of a system is directly proportional to the sum of forces (or net force) acting on it.
acceleration
What is different for a human on earth and the same for human on the moon?
Weight
If you run 200m on a 400m track, the linear distance you travel:
Will be greater than your linear displacement
What is the equation for linear acceleration?
change in velocity divided by change in time
What are suitable units for angular acceleration?
degrees/seconds^2
Newton's _______ law of motion explains what happens in the absence of an applied force.
first
What is the product of the net force applied to a system and the time interval of force application?
impluse
The maximum amount of shoulder extension in an athlete experiences when throwing the javelin is a ______________ factor?
kinematic
The stationary point in the environment, from which all measurements are made is called the:
origin
What is the angular displacement of a minute hand on an analog clock after 30 minutes have elapsed?
pi rad
Between quantitative and qualitative analysis, movement practitioners (e.g. coaches, teachers, personal trainers, physical therapists, etc.) mostly rely on ________ to provide feedback to performers during practice and rehabilitation
qualitative
Angular displacement is measured in degrees or:
radians
A quality that possesses a magnitude but no particular direction associated with it is called a:
scalar