Kinetic Concepts

Question 1

Kinetics

Answer 1

Study of the action of forces that cause and/or result from movement

Question 2

Linear Kinetics

Answer 2

Study of the forces associated with linear motion

Question 3

Angular Kinetics

Answer 3

Study of the forces associated with rotary motion

Question 4

Mass

Answer 4

• The quantity of matter contained in an object
• Unit = kg
• Scalar quantity

Question 5

Inertia

Answer 5

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

Question 6

Force

Answer 6

• Push or pull
• The product of mass and acceleration
• F = ma

Question 7

Net Force

Answer 7

Resultant force derived from the composition of 2+ forces

Question 8

Weight

Answer 8

• Gravitational force that the earth exerts on a body
• wt = ma(g)
• a(g) = -9.81 m/s^2

Question 9

Pound-Newton Conversion Factor

Answer 9

1 lb = 4.45 N

Question 10

Center of Gravity

Answer 10

• Point around which a body’s weight is equally balanced, no matter how the body is positioned
• aka Center of Mass
• Intersection of 3 cardinal planes

Question 11

Pressure

Answer 11

• Force per unit of area over which force acts
• P = F/A
• Units in the metric system are N/cm^2 and Pascals (Pa) and in the English system is psi

Question 12

Volume

Answer 12

• The amount of 3-dimensional space occupied by a body (V)

- V = lwh

Question 13

Density

Answer 13

• Mass per unit of volume

- ρ = m / V

Question 14

Specific Weight

Answer 14

Weight per unit of volume

Question 15

Impulse

Answer 15

• Product of force and the time over which the force acts
• J = Ft
• Unit = Ns

Question 16

Torque

Answer 16

• Rotary effect of a force
• Product of force and perpendicular distance from the force’s line of action to the axis of rotation
• Angular equivalent of linear force
• T = Fd
• Unit = Nm

Question 17

Other names for torque

Answer 17

• Moment of force

- Rotary force

Question 18

Other names for the perpendicular distance

Answer 18

• Moment arm

- Force arm

Question 19

Types of Mechanical Loads on the Human Body

Answer 19

Stresses
- Compression
- Tension
- Shear
Loads
- Torsion
- Bending
- Combined Loads

Question 20

Stress

Answer 20

Distribution of force within a body, quantified as force divided by the area over which the force acts

Question 21

Difference between stress and pressure

Answer 21

Stress is internal, but pressure is external

Question 22

Compression

Answer 22

Pressing or squeezing force directed axially through a body

Question 23

Tension

Answer 23

Pulling or stretching force directed axially through a body

Question 24

Shear

Answer 24

Force directed parallel to a surface

Question 25

Torsion

Answer 25

Load-producing twisting of a body around its longitudinal axis

Question 26

Bending

Answer 26

Asymmetric loading that produces tension on one side and compression on the other side

Question 27

Combined Loading

Answer 27

Simultaneous action of more than one of the pure forms of loading

Question 28

Effects of Loading

Answer 28

• Acceleration

- Deformation

Question 29

Deformation

Answer 29

Change in shape

Question 30

Elasticity

Answer 30

Property of matter where an object returns to its original size and shape when a force is removed

Question 31

Yield Point

Answer 31

• Point on the load deformation curve past which deformation is permanent
• Elastic limit

Question 32

Failure

Answer 32

Loss of mechanical continuity

Question 33

Repetitive Loading

Answer 33

Repeated application of a subacute load that is usually of relatively low magnitude

Question 34

Acute Loading

Answer 34

Application of a single force of sufficient magnitude to cause injury to a biological tissue