Exam 2 Flashcards
Studies the form, pattern, or sequencing of movement with respect to time
kinematics
T/F: kinematics can be analyzed quantitatively and qualitatively
True
Focuses on motion without considering forces
kinematics
examines forces causing movement
kinetics
only have magnitude (ex. mass, distance, speed, volume)
scalars
have both magnitude and direction (ex. velocity, force, acceleration, displacement)
vectors
total length traveled
distance
direct distance from initial to final position
displacement
____= distance / time
speed
____= displacement / time
velocity
velocity at a single moment
instantaneous velocity
total displacement dived by total time
average velocity
rate of change of velocity
acceleration
t/f: acceleration can be positive or negative
True
T/F: acceleration is never zero when velocity is constant
False
Speeding up in a positive direction –> _____ acceleration
Positive
Slowing down in a positive direction –> ____ acceleration
Negative
Speeding up in a negative direction –> ______ acceleration
Negative
Slowing down in a negative direction –> ______ acceleration
positive
A ______ is any object in free fall influenced only by gravity and air resistance.
projectile
T/F: Human movement can be analyzed as projectile motion
True
All projectiles follow a ____ trajectory
parabolic
Affected by gravity (-9.81 m/s^2 on earth), influences maximum height
vertical component
not affected by gravity; determines the distance traveled.
horizontal component
Time going up = ____ ____ ____ (assuming ground level
time going down
the direction relative to the horizontal
projection angle
straight up and down
vertical (90*)
half parabolic trajectory
horizontal (0*)
full parabolic trajectory
Oblique (0-90*)
Determines overall trajectory length
Projection Speed
The difference between initial height and landing height
relative height of projection
_____ and _____ motions are analyzed separately
vertical & horizontal
A projectiles horizontal motion remains _____, while vertical motion is influenced by _____.
constant ; gravity
T/F: Objects dropped and those launched horizontally from the same height hit the
ground at the same time.
True
Initial velocity is split into
horizontal velocity & vertical velocity
When analyzing projectile motion, the horizontal acceleration is _____.
zero
motion along a straight or curved line, with all parts of the body moving in the same direction/speed
linear motion
linear motion is also called
translation
rotation around the axis of rotation
angular motion
axis of rotation passes through the ______
joints center
are measured as movement away from anatomical position
joint angles
angular orientation of a body segment with respect to a fixed line of reference
body segment orientation
the instant center is the located center of a joint at given instant in time
instant center or rotation
the path of the instant center _____ as movement of the joint occurs
CHANGES
The sum of all angular changes that have occurred
angular distance
The change in angular position from initial to final positions
angular displacement
______: magnitude and direction
vector
_____: degrees, radians, and/or revolutions
units
In terms of angular motion:
Counterclockwise (______)
Clockwise (_____)
positive
negative
________ are the size of an angle subtended at the center of a circle by an arc equal in length to the _______ of the circle
radians ; radius
1 radian = ____ degrees
57.3
_____ are the number of times the movement completes a full 360 degrees around the axis of rotation
revolutions
________ is the angular distance covered, divided by the timer interval over which the motion occurred
angular speed
_______ is the rate of change in angular position or orientation of a line segment
angular velocity
_____ is the rate of change in angular velocity
angular acceleration
When is there zero angular acceleration?
when angular velocity is constant (can also be 0)
______ are the number of times the movement completes a full 360 degrees around the axis of rotation
revolutions
______: the angular distance covered, divided by the timer interval over which the motion occurred
Angular speed
3 Units of angular speed:
deg/s
rad/s
rev/s
is the rate of change in angular position or orientation of a line segment
angular velocity
T/F: Angular velocity is a scalar quantity
false
_____ is the rate of change in angular velocity
angular acceleration
T/F: Distance and speed are scalar qualities whereas displacement and velocity are vector quantities
True
In the absence of air resistance, the horizontal acceleration of a projectile is always equal to ______.
zero
T/F: If air resistance is disregarded, the horizontal component of a projectile is constant
True
The highest point in the trajectory of a projectile is the __________.
Apex
If a runner completes 1 full lap around a 400 meter track, what is their displacement?
0 meters
If velocity is constant, then acceleration is __________.
zero
T/F: For optimum performance, a long jumper and a high jumper would both try to use the same angle of projection.
False
T/F: At the peak of a projectile’s trajectory, the projectile’s vertical velocity is at its maximum (its largest value).
False
The Greek letter (delta) is used to represent what?
change in
In which of the following scenarios would acceleration be positive?
- Moving in a positive direction with decreasing speed
- Moving in a positive direction with increasing speed
- Moving in a negative direction with increasing speed
- None of the above
Moving in a positive direction with increasing speed
T/F: The clockwise direction in rotational motion is considered the negative direction.
True
Which of the following quantities are equal?
A. π radians and 180°
B. All of the above
C. 2π radians and 360°
D. 270° and 3/4 revolution
B.
T/F: A radian is a unit of angular measurement equal to approximately 57.3*.
True
T/F: The larger the radius of rotation, the greater the linear distance traveled by a point on a rotating body.
True
Which of the following is/are scalar quantities?
A. Angular acceleration
B. Angular distance
C. Angular velocity
D. All of the above
B.
What does the letter “r” stand for in the equation v = rω?
radius of rotation
T/F: It is very common for humans to move (e.g., walk, jog, run) with constant velocity.
False
If the knee joint goes through 100o of flexion during the down phase of a squat, what is the total angular distance traveled during 1 complete squat? (i.e., starting from standing upright, then squat down, and then return to standing)
0 *
Which quantity could be measured in units of rad/s?
A. angular displacement
B. angular acceleration
C. angular velocity
D. linear displacement
C.
T/F: The instant center of rotation is always the same location within a given joint.
False
