CH2: Time Flashcards
What is time?
- Time is the measure of succession between two events, in other words, the temporal distance between two events
- Considered the 4th dimension
The first three dimensions we have seen relate to space. Unlike space, time extends in only __________ direction
one. Because time has only one direction, this direction is referred to as the arrow of time.
How does time exist?
Tim exists because of the Second Law of Thermodynamics, which is the law of entropy
What is entropy?
Entropy is the amount of chaos or disorder present in a closed system, such as the universe.
The most common measure of entropy is what?
The size of the universe. The universe
expands, meaning there is more space for energy and particles to go, which increases chaos. As the universe continues to expand, time continues to move forward.
Ancient Egyptians divided 1 day into…
10 hours of daylight + 2 hours of twilight + 12 hours of night
Ancient Babylonians measured astronomical events with a base-60 system…
- 1 hour divided into 60 minutes
- 1 minute divided into 60 seconds
1 second is the time for transition between __________
hyperfine states of cesium-133
What is the difference between the base-60 system and the base-10 system?
In the “base-60” system, these simple fractions reduce the need for complex decimal values, which would be critical before modern calculators and computers. More simple fractions can be developed in the “base-60” system versus the “base-10” system
What is Rhythm?
- Temporal sequence of events within a task
- Relative timing between events within a task
What is Tempo?
- Total time to perform a task or sequence of events
- Absolute time to perform all events
- Frequency of performing a task
What percent of the freestyle swimming stroke is Early Pull-Through (Entry to Bottom Dead Centre)?
48%
What percent of the freestyle swimming stroke is Late Pull-Through (Bottom Dead Centre to Exit)?
28%
What percent of the freestyle swimming stroke is Early Recovery (Exit to Top Dead Centre)?
16%
What percent of the freestyle swimming stroke is Late Recovery (Top Dead Centre to Entry)?
8%
Even at different swimming speeds, the swimmer will display __________ frequency.
the same
What percent of the butterfly swimming stroke is Early Pull-Through (Entry to Bottom Dead Centre)?
52%
What percent of the butterfly swimming stroke is Late Pull-Through (Bottom Dead Centre to Exit)?
30%
What percent of the butterfly swimming stroke is Early Recovery (Exit to Top Dead Centre)?
9%
What percent of the butterfly swimming stroke is Late Recovery (Top Dead Centre to Entry)?
9%
What is frequency?
The rate at which an event occurs or is repeated over a particular time period
How is frequency calculated?
- f = # events / time
- f = 1 / time between events
- SI Unit: Hertz (Hz)
What is heart rate?
Number of beats per minute
What is the frequency of digital video: 30 frames per second?
Frequency = 30 Hz
What is the time interval of digital video: 30 frames per second?
Time interval = 1 s / 30 = 0.033 s
- Digital video captures 1 frame (image) every 0.033 s
What are the two phases in a gait cycle?
stance and swing
Gait cycle: what is stance?
Stance is when the lower limb is in contact with the ground (60% of the time is spent here)
Gait cycle: what is swing?
Swing is when the lower limb is not in contact with the ground (40% of the time is spent here)
What is the “rhythm” of gait for running
40% of time in stance, 60% time in swing
Once __________ has been mastered, it can be performed at a faster __________.
the rhythm, tempo
How can we control or manipulate an individual’s rhythm and/or tempo?
Metronome, music, verbal cues
