Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
The velocity of an object is the rate at which its position changes over time. In mathematical terms,
Q: What are the standard units of velocity?
The SI units of velocity are meters per second, of course.
In the example below, suppose that the butterfly takes t = 5 seconds to flutter from the pink flower to the white one.
Images courtesy of
Wikipedia
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Wikipedia
Q: What is the velocity of the butterfly?
Now, we need to be careful to distinguish two varieties of velocity. We'll encounter each one at times throughout this semester.
The average velocity is based on the total displacement over some extended time interval. All that matters is the starting and ending locations, and the total time taken for the journey.
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Wikipedia
and
Wikipedia
On the other hand, the instantaneous velocity is the velocity of an object at one particular moment in time.
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Wikipedia
and
Wikipedia
Consider the Apollo 11 moon mission: astronauts travelled from the Earth to the Moon, spent about 21 hours on the surface, then returned to the Earth. The entire trip took a total of about 8 days.
Images of the Earth and Moon courtesy of
NASA
and
NASA
Q: What was the average velocity of the astronauts?
Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
