Quiz #10 Flashcards
Characteristic patterns:
- Bimodal (two symmetrical humps)
- Vertical 1-1.2 BW
- A/P 0.15 BW
walking
Characteristic patterns:
- Passive peak (heel strike)
- Active peak (forefoot)
- Vertical 2-5 BW
- A/P 0.5 BW
Running
An impulse changes the momentum of an object
Impulse - momentum relationship
impulse =
change in momentum
Area under Force-Time curve =
impulse
impulse = mass x acceleration
impulse = m(change in v / change in t)
impulse - momentum relationship
Major contributors to impulse
mass and change in velocity
Types of friction:
Friction acting between two surfaces that are not moving relative to one another
static
During stationary conditions, it is represented on FBD by _
horizontal force
During dynamic conditions, it must be represented on FBD by an _
opposing force
Types of friction:
Friction acting between two surfaces that are moving relative to one another
Kinetic
Kinetic Friction:
Resistive force between objects that slide or rub against each other
sliding
Kinetic Friction:
Resistive force when objects roll over a supporting or contacting surface
rolling
- acts parallel to the area of contact
- opposes motion or the tendency for motion
static and sliding friction
Depends on two things:
- Coefficient of friction
- The perpendicular force
friction force
Does size of area of contact influence friction?
No
Under static conditions:
- F friction = F applied
- coefficient of static friction calculated just before _ occurs
sliding
Under kinetic (sliding) conditions
- coefficient of sliding friction influence motion
- at low speeds is _
constant
Used to understand when slipping likely
dynamic coefficient of friction
The resistance of an object to a change in motion
inertia
Linear inertia
quantified as mass
The property of an object that resists changes in angular motion
- quantified as the object’s moment of inertia
angular inertia
Humans manipulate their moments of _
inertia
Moment of inertia affected by:
- mass
- How the mass is distributed relative to the _
axis of rotation
When mass is distributed closer to the axis of rotation the moment of inertia is _
smaller
