Basic Biomechanics Flashcards

1
Q

Biomechanics involves the study of? 2

A

Statics and Dynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define statics:

A

Study of forces acting on rigid bodies in equilibrium or at constant velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the 3 subtypes of dynamics?

A

Kinetics
Kinematics
Kinesiology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define kinetics

A

Study of forces acting on a rigid body and resultant motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define Kinematics?

A

Study of motion of a rigid body with no concerns of the forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is Newtons first law?

A

Inertia - a body in motion will remain in motion at a constant velocity in a straight line. Sum of external forces = zero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is newtons second law?

A

Action
F = ma
Useful for dynamic analysis
A body with a non-zero net force will accelerate in the direction of the force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is newtons 3rd law?

A

Reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a moment of force?

A

The effect of a force at a perpendicular distance from an axis - results in rotational movement and angular accelaration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Definition of energy?

A

Ability to do work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is potential energy?

A

Ability to do work due to body position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is kinetic energy?

A

Work required to stop/move a body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the working length?

A

Unsupported length of construct = length btw most distal point of prox fixation and most prox point of distal fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is moment of inertia?

Second moment area/ Area moment of inertia

A

Ability of a structure to resist deformation - related to bending rigidity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is polar moment of inertia?

A

Ability of an object to resist torsion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Definition of power?

A

Work/time

17
Q

What are degrees of freedom?

A

Number of independent modes of motion in a joint

18
Q

What is the relationship between DOF and constraint forces?

A

For every 1 DOF = 2 constrain forces

19
Q

What is a 1st class lever?

A

Head
Atlanto occipital joint
Fulcrum in middle

20
Q

What is a 2nd class lever?

A

Foot
Fulcrum on one side
Load then action force

21
Q

What is a 3rd class lever?

A

Elbow
Fulcrum on one side
Action force then load

22
Q

Define a lever?

A

Rigid structure that turns around a fixed point

23
Q

How are bending forces calculated?

A

Force x distance from neutral axis over moment of inertia

24
Q

MOI of a rectangular object =

A

(width x height) to 3rd power

wh cubed div 12

25
Q

What is bending rigidity =

A

MOI x Young’s modulus

26
Q

What is the MOI of a solid cylinder =

A

radius power of 4

pi x radius ^4 div 4

27
Q

What is the MOI of hollow cylinder?

A

Radius^4 minus inner diameter ^4 div 4

28
Q

How are shear stresses calculated?

A

Force x distance from axis of twist div polar moment of inertia

29
Q

How is the torsional rigidity calculated

A

PMA x shear modulus

30
Q

Polar moment of inertia of a solid rod =

A

pi r^4 div 2!!!

31
Q

Polar moment of inertia of a hollow rod =

A

pi r^4 - I^4 div 2