Torques, Angular Kinetics/Kinematics Flashcards

0
Q

Since producing torque requires force, there just be: (3)

A

Magnitude (how much)
Direction (linear and line of action)
Point of application

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

How to create more torque (without changing force):

A

Move “hand farther away from axis = inc moment arm
T= F*r
r = moment arm

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

The _______ the moment arm the greater the _______.

A

Longer/ greater

Torque

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

When forces are the _______ with a ______ moment arm = ____ _____

A

Same
Long
Greater torque

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

When is the moment arm the longest in the human body (muscle and joint systems?

A

90 degrees

- extend slightly- attachment moves closer to axis = moment arm shorter – same with < 90dg

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

What determines the amount of torus we generate?

A
Moment arm length
Muscular force (strength of contraction)
Position/angle of the joint
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Longer radius =

A

Greater velocity for any given angle

S=wr = change in angle / t

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

Longer club =

A

Greater linear velocity = greater displacement

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

Components of Angular Acceleration

A

Tangential

Centripetal

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

The Moment of Inertia equation applies best to:

A

Objects in which distribution of mass is constant through the rotation

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

Can angular moment be changed after leaving the ground?

A

No, but angular velocity can change (rotate faster = dec moment of inertia

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

Angular Momentum: changes in linear motion

Rigid and Non-Rigid

A
  • Rigid object: generally depends on change in angular velocity (w)
  • Non-Rigid: easily influenced by changes in avg. velocity (w) OR the moment of inertia (I)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why does Newton’s 1st not require the angular velocity to remain constant?

A

change in angular velocity countered by change in moment of inertia
- H~= (dec) I * (inc) w

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

The _______ the object is immersed the ______ the ______.

A

Deeper submerged
Greater
Pressure

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

What is the name for when the buoyant force is equal to the weight of the displaced fluid?

A

Archimedes Principle

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

How does temperature effect the SG water?

A

high temp = dec SG (molecules farther apart)

Cold temps = inc SG (molecules closer together)

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

When will an object float?

A

When an object has SG less than water

- will weight less than an equal volume of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When will an object sink?

A

When an object has a SG greater than water

- weight more than an equal volume of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two components that determine if an object will float or sink?

A

Density

Specific Gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is a dynamic fluid force dependent on?

A

Density of fluid
SA of the object
Relative Velocity of the object to the fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the 2 major components of dynamic fluid force?

A

Drag

Lift

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 2 types of drag forces?

A

Surface

Form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Surface Drag- Cd is influenced by:

A
  1. Roughness of the object surface

2. Fluid viscosity (friction btw fluid layers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Form Drag- Cd is influenced by:

A
  1. Objects shape

2. Surface texture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
How do you reduce drag? (4)
1. Make body surface/ clothing smoother 2. Streamline shape 3. Reduce SA exposed to flow 4. Perform at: high altitude, in warm water, draft, run with wind
25
How does lift work on an airfoil?
- flow across the top is faster than the bottom - creates L pressure on top and H pressure on bottom - pressure travels H --> L
26
How does the Magnus Effect work?
- H pressure builds on the surface that is spinning against the flow - L pressure on surface spinning "with" the flow (less resistance to flow) - object moves toward L pressure
27
How does Bernoulli's Principle work?
- L pressure created on top ( fast moving fluids = L pressure) - H created on the bottom - H --> L
28
Relationship btw Angular and Linear Velocity
avg linear speed of a point on a rotating obj = avg angular velocity of the object times the radius
29
Angular Interpretation of Newton's 1st
- angular momentum remains constant unless acted on by an external force (remains in rotational motion unless acted upon)
30
Angular Interpretation of Newton's 2nd
- net torque produces angular accel proportional to: 1. Torque (magnitude) in the 2. Direction of the torque and 3. Inversely proportional to the Moment of Inertia
31
Angular Impulse and Momentum Relationship
- same as linear - ang impulse = ang momentum. - inc torque OR the time a torus is applied = inc ang momentum
32
Angular Interpretation of Newton's 3rd
For every torque exerted by one obj on another, there is an equal (magnitude) and opposite (direction) torque exerted by the 2nd obj on the 1st - 2 obj share the same axis
33
Eccentric Force
- an external force not direct through an objects CoG - torque - linear and ang motion
34
Centric Force
- an external force directed through an objects CoG - NO torque - linear motion only
35
Laminar Flow
Fluid molecules stay close to the obj surface
36
Angular Motion
When all points on an object move in circular paths about the same axis (do NOT travel the save distance) - angle formed by 2 lines/planes or one line and one plane intersecting
37
Centripetal Acceleration
Linear accel directed toward the axis of rotation
38
Bernoulli's Principle
Fast moving fluid exerts less pressure than slow moving fluids
39
Lift Force
- Dynamic fluid force - acts PERPENDICULAR to the relative motion of the object (with respect to fluid) - not always upward (spoiler) - often generated when the obj is longer in the dimension // to the flow
40
Tangential Acceleration
The component of linear accel tangent to the circular oath of a rotating object - occurs even if the object continues to rotate about its axis
41
Archimedes Principle
The size of the buoyant for is equal to the weight of the fluid displaced by an object
42
Drag Force
- dynamic fluid force - acts in OPPOSITION to the relative motion of the object (with respect to fluid) - tends to slow the object if it's the only force acting
43
Relative Angular Position
Both lines/planes can move | - elbow: forearm and upper arm can move
44
Absolute Angular Motion
One line/plane is fixed | - elbow- move forearm, keep upper arm still = bicep curl
45
Torque: Pulling at an angle (same amount of force)
Can pull with same amount of force and SHORTEN the moment arm
46
What is the Magnus Effect?
A lift force created by the SPIN of an object
47
Dynamic Fluid Force
- forces exerted on an object as it moves through a fluid and/or as a fluid moves past the object - dependent on: 1. Density of fluid 2. SA of object 3. Relative velocity of the object to the fluid
48
2nd Class Levers
Wheelbarrow Nutcracker (metal) Human Body- ball of foot (a), plantar flexors (F), body aligned over tibia (R) _a____ ⬇️R____⬆️F
49
Buoyant Fluid Forces
- forces due to immersion | - acts upward (vertical) on an object immersed in fluid
50
Specific Gavity
The ratio of the weight of an object to the weight of an equal volume of water Weight obj/weight H2O
51
Surface Drag
Caused by the friction btw an object's surface and the fluid it's moving through - roughness - fluid viscosity - skin friction
52
Form Drag
Related to type of flow: laminar or turbulent - ⬆️ with turbulent flow - influenced by- object shape and surface texture
53
Moment of Inertia
- quantity of angular inertia - dependent on: 1. Distribution of amass 2. Axis of rotation - when smaller (mass closer to axis) = ⬆️ angular velocity/accel
54
Torque
- a turning/ rotary effect produced by force - product of Force and the perpendicular distance from the line of faction of the force to the axis of rotation - result of an OFF AXIS FORCE causing a turning effect
55
3rd Class Levers
- rowing (upper hand) - human muscle and joint systems - most levers within the human body a____⬆️F____⬇️R
56
Pressure
- buoyant force per unit area (N/m2) - acts in all directions on immersed obj - ⬆️ linearly with depth
57
Radius of Gyration
- represents an obj's mass distribution relative to the axis - changes if: The axis of rotation changes Distribution of mass about the axis changes
58
Moment Arm
Shortest distance from axis of rotation to the line of action of the force - always perpendicular to the line of caption (right angle)
59
1st Class Levers
Seesaw ⬇️F_____a______⬇️R Scissors Lever to move heavy objects Nodding head- atlas vertebrae ( F= m contraction, R= weight of head)
60
Angular Momentum if the Human Body
The sum of the angular momenta of ALL the BODY SEGMENTS | - approximates the overall momentum of the body
61
Turbulent Flow
Fluid molecules flow away from the object's surface- may create a vacuum (L pressure)
62
Force Couple/Couple
- a pair of non-colinear external forces, EQUAL in MAGNITUDE but OPPOSITE in DIRECTION - torque - angular motion only
63
Relative Velocity
The difference btw an objects velocity and fluid velocity