Lecture 1 Kinetics and Kinematics

Question 1

What is kinematics?

Answer 1

The study of motion without considering the forces that cause movement.

Question 2

What are the types of displacement in kinematics?

Answer 2

Translatory, Rotary, and General Motion (combination of translation and rotation).

Question 3

What is translatory motion?

Answer 3

Movement in a straight line.

Question 4

What is rotary motion?

Answer 4

Movement around a fixed axis.

Question 5

What is general motion?

Answer 5

A combination of translatory and rotary movements.

Question 6

What is the center of rotation (COR)?

Answer 6

The fixed point around which rotary motion occurs.

Question 7

What is linear displacement?

Answer 7

Movement in a straight line, measured in meters or feet.

Question 8

What is angular displacement?

Answer 8

Movement around an axis, measured in degrees.

Question 9

What is the unit of measurement for rotation?

Answer 9

Degrees, with a maximum of 360°.

Question 10

What is the unit of measurement for translation?

Answer 10

Inches, feet, meters, etc.

Question 11

What is speed?

Answer 11

Displacement per unit of time, regardless of direction.

Question 12

What is velocity?

Answer 12

Displacement per unit of time in a specific direction.

Question 13

What is acceleration?

Answer 13

The rate of change of velocity over time.

Question 14

What is force?

Answer 14

A push or pull exerted by one object on another, measured in Newtons (N) or pounds (lb).

Question 15

What is Newton’s First Law of Motion (Law of Inertia)?

Answer 15

An object will remain at rest or move in a straight line unless acted upon by an external force.

Question 16

What is Newton’s Second Law of Motion (Law of Acceleration)?

Answer 16

Force equals mass times acceleration (F=ma).

Question 17

What is Newton’s Third Law of Motion (Law of Reaction)?

Answer 17

For every action, there is an equal and opposite reaction.

Question 18

What are external forces?

Answer 18

Forces acting on the body from outside, like gravity and friction.

Question 19

What are internal forces?

Answer 19

Forces generated within the body, like muscle contractions.

Question 20

What is gravity’s role in movement?

Answer 20

Gravity acts as a constant external force, pulling objects downward.

Question 21

What is the center of mass (COM)?

Answer 21

The point where the body’s mass is equally distributed.

Question 22

What is the base of support (BOS)?

Answer 22

The area beneath an object or person that supports their weight.

Question 23

What increases stability in the body?

Answer 23

A wider base of support and a lower center of mass.

Question 24

What is static equilibrium?

Answer 24

When an object is at rest, with balanced forces.

Question 25

What is dynamic equilibrium?

Answer 25

When an object moves at a constant velocity with balanced forces.

Question 26

What are tensile forces?

Answer 26

Forces that pull in opposite directions along the same segment.

Question 27

What are compressive forces?

Answer 27

Forces that push two body segments together.

Question 28

What are shear forces?

Answer 28

Forces parallel to the contacting surfaces that can cause movement.

Question 29

What is friction?

Answer 29

A force that opposes motion between two contacting surfaces.

Question 30

What is torque?

Answer 30

The rotational force around an axis, calculated as force times moment arm (T=F*MA).

Question 31

What is a moment arm (MA)?

Answer 31

The shortest distance between the axis of rotation and the line of action of the force.

Question 32

What is a force couple?

Answer 32

Two equal and opposite forces applied to the same object at different points, causing rotation.

Question 33

What is an anatomical pulley?

Answer 33

A structure that changes the direction of a muscle's pull to increase its efficiency.

Question 34

What is concentric contraction?

Answer 34

Active shortening of a muscle during movement.

Question 35

What is eccentric contraction?

Answer 35

Active lengthening of a muscle while controlling movement.

Question 36

What is isometric contraction?

Answer 36

Muscle contraction without joint movement.

Question 37

What is a first-class lever?

Answer 37

A lever where the fulcrum is between the effort and the resistance.

Question 38

What is a second-class lever?

Answer 38

A lever where the resistance is between the fulcrum and the effort.

Question 39

What is a third-class lever?

Answer 39

A lever where the effort is between the fulcrum and the resistance.

Question 40

What is mechanical advantage (MAd)?

Answer 40

The ratio of the effort arm to the resistance arm in a lever system.

Question 41

When is mechanical advantage greater than 1?

Answer 41

In second-class levers, where less effort is needed to move a load.

Question 42

When is mechanical advantage less than 1?

Answer 42

In first- and third-class levers, where more effort is needed but greater speed and range of motion are achieved.

Question 43

What is open chain movement?

Answer 43

Movement where the distal segment is free to move.

Question 44

What is closed chain movement?

Answer 44

Movement where the distal segment is fixed.

Question 45

What is the line of gravity (LOG)?

Answer 45

The vertical line through an object's center of mass.

Question 46

What is equilibrium in biomechanics?

Answer 46

A state where all forces and torques acting on a body are balanced.

Question 47

What is a resultant force?

Answer 47

The combined effect of two or more forces acting on an object.

Question 48

What is angular velocity?

Answer 48

The rate of change of angular displacement, measured in degrees per second.

Question 49

What is linear velocity?

Answer 49

The rate of change of position in a straight line, measured in meters per second.

Question 50

What is the law of acceleration?

Answer 50

An object's acceleration is proportional to the unbalanced forces acting on it and inversely proportional to its mass.

Question 51

What is a moment of inertia?

Answer 51

The resistance of an object to rotational acceleration, dependent on mass and distance from the axis.

Question 52

What is the function of ligaments in movement?

Answer 52

To provide stability by limiting excessive joint movement.

Question 53

What is the function of tendons?

Answer 53

To connect muscles to bones, transmitting forces to create movement.

Question 54

What is the center of gravity (COG)?

Answer 54

The point where the total weight of the body is considered to be concentrated.

Question 55

How does posture affect the center of mass?

Answer 55

Changing posture can shift the center of mass, affecting balance and stability.

Question 56

What is the significance of the screw home mechanism?

Answer 56

It provides stability to the knee in full extension.

Question 57

What is curvilinear motion?

Answer 57

Motion along a curved path.

Question 58

What is the impact of joint distraction forces?

Answer 58

They separate joint surfaces and can relieve pressure or aid in joint mobilization.

Question 59

What is the impact of joint reaction forces?

Answer 59

They occur when two body segments are compressed together, influencing joint stability.

Question 60

What is the role of muscle forces in joint stability?

Answer 60

Muscles generate forces that stabilize joints during movement.

Question 61

What is the significance of the moment arm in torque production?

Answer 61

A longer moment arm increases the torque produced by a given force.