Biomech- midterm1

Question 1

What is Kinematic?

Answer 1

Study of the motion without references to the forces that cause the movement.

Question 2

What is Kinetic?

Answer 2

Relates the forces acting on bodies to the resulting motion.

Question 3

What does the Frontal plane do?

Answer 3

Divides front and back; associated with abductions and adductions.

Question 4

What does the Sagittal plane do?

Answer 4

Divides right and left; associated with flexion and extension.

Question 5

What does the Transverse plane do?

Answer 5

Divides top and bottom; associated with external and internal rotation.

Question 6

What is Translation in Kinematics?

Answer 6

Movement from one place to another where all points move through the same distance.

Question 7

What are the types of Translation?

Answer 7

Linear and curvilinear.

Question 8

What is Rotation in Kinematics?

Answer 8

Angular motion about an axis, where all points move through the same angle.

Question 9

What is General motion?

Answer 9

Combination of translation and rotation; most often, it is both.

Question 10

What is Position in Kinematics?

Answer 10

Uses a spatial reference system to standardize measurements, typically a standard Cartesian coordinate system.

Question 11

What does Movement represent?

Answer 11

Change in x, y (location) over time.

Question 12

How is the human body modeled for gross motor movement analysis?

Answer 12

As a hinged, linked series of rigid bodies.

Question 13

What is Symmetric modeling of limbs?

Answer 13

Both limbs are mirror images.

Question 14

What is Non-symmetric modeling of limbs?

Answer 14

Limbs function independently.

Question 15

What is the trade-off in viewing distance of an athlete?

Answer 15

Viewing distance affects resolution and size of field of view; far view allows seeing entire movement, while close view provides better resolution and angle but minimizes the portion of movement visible.

Question 16

What are tools for measuring kinematic quantities?

Answer 16

Cinematography and videography, real-time tracking of LEDs, computer-linked cameras, goniometer/electrogoniometer, photocells, light beams and timers, accelerometer.

Question 18

What is a scalar?

Answer 18

Only a magnitude: mass, volume, speed

Scalars do not have a direction associated with them.

Question 19

What is a vector?

Answer 19

Has magnitude and direction (usually expressed with arrows)

Vectors represent quantities that have both size and direction.

Question 20

Name two types of kinematic vector quantities.

Answer 20

• Displacement
• Velocity
• Acceleration

Kinematic quantities describe the motion of objects.

Question 21

What is the resultant vector?

Answer 21

The vector you are adding

The resultant vector is the sum of two or more vectors.

Question 22

What does resolving vectors mean?

Answer 22

Splitting vectors into 2 vectors that are perpendicular to each other

This process simplifies the analysis of vector quantities.

Question 23

Define inertia.

Answer 23

Tendency for a body to resist change in its state of motion

Inertia is a property of matter that depends on mass.

Question 24

What is mass?

Answer 24

Quantity of matter contained in an object (mass is scalar- only magnitude)

Mass does not change regardless of the object’s location.

Question 25

Define force.

Answer 25

A push or pull acting on an object (force is a vector- magnitude and direction) ## Footnote Forces can cause changes in the motion of an object.

Question 26

What are internal forces in human movement?

Answer 26

* Muscle force * Joint force (ligament forces, bone on bone forces) ## Footnote Internal forces originate from within the body.

Question 27

What are external forces in human movement?

Answer 27

* Gravity (weight) * Ground reaction force * Friction ## Footnote External forces act on the body from the environment.

Question 28

What is the net force?

Answer 28

Force resulting from the vector addition of two or more forces ## Footnote Net force determines the resulting motion of an object.

Question 29

What is weight?

Answer 29

Force due to gravity (amount of gravitational attraction between object and earth) ## Footnote Weight is a vector quantity that can change based on location.

Question 30

Define the center of gravity.

Answer 30

Point where a body weight is equally balanced no matter how the body is positioned ## Footnote The center of gravity affects stability and balance.

Question 31

What is torque?

Answer 31

Rotary effect of a force (also called moment of force) ## Footnote Torque influences rotational motion of an object.

Question 32

What is the formula for torque?

Answer 32

Torque = force x moment arm ## Footnote The moment arm is the perpendicular distance from the line of action of the force to the axis of interest.

Question 33

What does impulse represent?

Answer 33

The integration of force over time ## Footnote Impulse is calculated as the area under a force vs. time curve.

Question 34

Fill in the blank: Torque is that which causes or attempts to cause a change in the _______.

Answer 34

[rotational motion] ## Footnote Understanding torque is essential in mechanics and physics.

Question 35

How is the skater's displacement measured?

Answer 35

In a straight line from start to finish.

Question 36

Define velocity in the context of motion.

Answer 36

Change in position (displacement) over change in time.

Question 37

What is acceleration?

Answer 37

Rate of change in linear velocity over a given time.

Question 38

When is acceleration equal to 0 in relation to time?

Answer 38

At peak velocity.

Question 39

What is the difference between average and instantaneous quantities?

Answer 39

Average: value over the whole time period; Instantaneous: value at a specific instant.

Question 40

What does the slope of the displacement vs time curve represent?

Answer 40

Instantaneous velocity.

Question 41

What indicates a negative velocity on a graph?

Answer 41

Any slope down.

Question 42

What indicates a positive velocity on a graph?

Answer 42

Any slope up.

Question 43

What does a horizontal line on a velocity graph indicate?

Answer 43

Velocity = 0. or constant

Question 44

What is the method for gathering kinematic data?

Answer 44

Taking repeated pictures at even time spacing.

Question 45

What is projectile motion?

Answer 45

A body in free fall subject only to forces of gravity and air resistance.

Question 46

What are the horizontal and vertical components of projectile motion subject to?

Answer 46

Horizontal: air resistance; Vertical: air resistance and gravity.

Question 47

What is the acceleration due to gravity?

Answer 47

-9.81 m/s^2.

Question 48

What happens to vertical velocity at the apex of a projectile's flight?

Answer 48

It is 0 m/s.

Question 49

What factors influence the trajectory of a projectile?

Answer 49

* Angle of projection * Projection speed * Relative height of projection

Question 50

What angle of projection provides the maximum range?

Answer 50

45 degrees.

Question 51

What is the relationship between projection speed and distance traveled?

Answer 51

Speed has a squared effect on distance.

Question 52

What are the equations of constant acceleration for vertical and horizontal components?

Answer 52

Vertical: constant acceleration of 9.81 m/s^2; Horizontal: constant acceleration of zero.

Question 53

What is angular motion?

Answer 53

Rotation about an axis.

Question 54

Define relative angles.

Answer 54

Angles formed between the longitudinal axes of adjacent body segments.

Question 55

What is an absolute angle?

Answer 55

Angular orientation of a body segment with respect to a fixed line of reference.

Question 56

What is angular displacement?

Answer 56

Change of angular position from start to end.

Question 57

What is the unit of angular measurement that is unitless?

Answer 57

Radian.

Question 58

What does clockwise rotation represent in angular motion?

Answer 58

Negative rotation.

Question 59

What does counterclockwise rotation represent in angular motion?

Answer 59

Positive rotation.

Question 60

What is tangential acceleration?

Answer 60

Component of acceleration directed along a tangent to the path of motion.

Question 61

What is radial acceleration?

Answer 61

Component of acceleration directed toward the center of curvature.

Question 62

What does the average angular kinematic represent?

Answer 62

Determined by the length of the time interval selected.

Question 63

How is the relationship between linear and angular distance expressed?

Answer 63

Velocity = radius x angular distance.