2.1 Relative Motion
If you see me move past you at + 3.5 m/s, I see you move past me at _________________.
Use this picture for the rest of the questions in this section.
What is the velocity of the fly relative to the Earth?
How much Earth distance would the bus cover in an hour?
Assuming the bus is long enough, how much bus distance can the fly cover in an hour?
Assuming the bus is long enough, how much Earth distance can the fly cover in an hour?
If the fly flew backwards at the same speed, how much bus distance would it cover in an hour?
If the fly flew backwards at the same speed how much Earth distance would it cover in an hour?
How could fve = 0?
2.2 & 2.3 Speed and Velocity
______________ are quantities that need direction and __________________. They will always have a ________ or ________________ sign to show __________________.
Conversely, ________________ are quantities that do NOT need direction. They will never have a ________.
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Scalar |
Vector |
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Length: |
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Position Change: |
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Velocity Change: |
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We talk about two types of speed:
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1. ______________ speed =
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Find the average speed of a slug who walks 18.5 inches in 2.5 minutes. |
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2. __________________________ speed = speed at any instant.
To find the instantaneous speed, you find the ________________ and discard the __________________.
A
Displacement-time graph of no motion looks like this:
The
Displacement-time graph of constant velocity looks like this:
The __________ of a Displacement-time graph = the __________________________ _______________ at that time.
The Displacement-time graph of this motion:
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t = 0ŕ3 seconds |
Velocity = +5 feet/second |
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t = 3ŕ5 seconds |
Velocity = +2 feet/second |
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t = 5ŕ10 seconds |
Velocity = -3 feet/second |
looks like:
2.4 Acceleration
How quickly or slowly something changes its velocity is ______________________.
Acceleration can occur in 3 ways:
1. ________________ ____
2. ________________ ____
3. ________________ __________________
On a Displacement-time graph, accelerations are ____________.
Make a Displacement-time graph for this motion:
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t = 0ŕ2 seconds |
Positive Acceleration |
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t = 2ŕ4 seconds |
Constant Velocity |
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t = 4ŕ7 seconds |
Negative Acceleration |
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t = 7ŕ10 seconds |
No Motion |
When an object is in free “fall”, it is only affected by ________________.
This rarely occurs because of ______ ____________________.
The term free “fall” is deceiving because an object could be going ____ and still be in free fall since it is still only affected by ____________.
When an object free “falls”, it accelerates at ______ _______.
