graph behavior

course Mth 173

2/26 12

Question: `q query problem 2.3.37 . Which graph matches the graph of the bus and why?

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Your solution:

The bus (a), with many stops would match graph (II).

confidence rating #$&*: 3

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Given Solution:

** The bus only makes periodic stops, whereas the graph for III only comes to a stop once. I would matche the bus with II. **

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Self-critique (if necessary): *graph (I) would match (b) and (III) would match (c).

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Self-critique rating #$&*: 3

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Question: `q describe the graph of the car with no traffic and no lights

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Your solution:

Graph (I) would accelerate to a top speed, then level off for a extended period of time.

confidence rating #$&*: 3

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Given Solution:

** The car matches up with (I), which is a continuous, straight horizontal line representing the constant velocity of a car with no traffic and no lights. *&*&

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Self-critique (if necessary): OK

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Self-critique rating #$&*: 3

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Question: `q describe the graph of the car with heavy traffic

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Your solution:

Graph (III) is very non-linear with constant speed changes and a low overall speed average.

confidence rating #$&*: 3

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Given Solution:

** The car in heavy traffic would do a lot of speeding up and slowing down at irregular intervals, which would match the graph in III with its frequent increases and decreases. **

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Self-critique (if necessary): OK

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Self-critique rating #$&*: 3

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Question: `q query 2.4.11 5th, 2.4.10 4th; 2.5.10 (was 2.4.8) q = f(p) (price and quantity sold)what is the meaning of f(150) = 2000?

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Your solution:

F($p) = q

At $150, 2000 units are sold.

confidence rating #$&*: 3

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Given Solution:

*&*& q = 2000 when p = 150, meaning that when the price is set at $150 we expect to sell 2000 units. *&*&

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Self-critique (if necessary): OK

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Self-critique rating #$&*: 3

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Question: `q what is the meaning of f'(150) = -25?

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Your solution:

F’ is the rate of change, so at $150 the rate of change is -25 units.

confidence rating #$&*: 3

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Given Solution:

** f' is the derivative, the limiting value of `df / `dp, giving the rate at which the quantity q changes with respect to price p.

If f'(150) = -25, this means that when the price is $150 the price will be changing at a rate of -25 units per dollar of price increase.

Roughly speaking, a one dollar price increase would result in a loss of 25 in the number sold. **

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Self-critique (if necessary): *Units per dollar.

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Self-critique rating #$&*: 3

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Question: `q query problem 2.4.23 5th; 2.4.18 4th; 2.4.7 graph of v vs. t for no parachute.

Describe your graph, including all intercepts, asymptotes, intervals of increasing behavior, behavior for large |t| and concavity, and tell why the graph's concavity is as you indicate.

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Your solution:

My graph starts at (0,0) and increases violently at an decreasing rate. A horizontal asymptote is at the terminal velocity on the y-axis and the graph is concave down.

confidence rating #$&*: 3

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Given Solution:

** When you fall without a parachute v will inrease, most rapidly at first, then less and less rapidly as air resistance increases.

When t = 0 we presume that v = 0.

The graph of v vs. t is therefore characterized as an increasing graph beginning out at the origin, starting out nearly linear (the initial slope is equal to the acceleration of gravity) but with a decreasing slope. The graph is therefore concave downward.

At a certain velocity the force of air resistance is equal and opposite to that of gravity and you stop accelerating; velocity will approach that 'terminal velocity' as a horizontal asymptote.

The reason for the concavity is that velocity increases less and less quickly as air resistance increases; the approach of the velocity to terminal velocity is more and more gradual **

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Self-critique (if necessary): *nearly linear from start.

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Self-critique rating #$&*: 3

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Question: `q What does the t = 0 acceleration indicate?

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Your solution:

The time has not yet started, so you are still on the plane presumably.

confidence rating #$&*: 2

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Given Solution:

** t = 0 acceleration is acceleration under the force of gravity, before you build velocity and start encountering significant air resistance.

Acceleration is rate of velocity change, indicated by the slope of the v vs. t graph. **

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Self-critique (if necessary): OK

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Self-critique rating #$&*: 3

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Question: `q Query Add comments on any surprises or insights you experienced as a result of this assignment.

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Self-critique (if necessary): As I would expect would be the case to most students, graphs and graph behavior is easier to comprehend.

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Self-critique rating #$&*: 3

&#This looks very good. Let me know if you have any questions. &#