# Solve: Velocity and Vectors

The page has Graph A, B and C. I hope this works here, but graph A versus time looks like this: The dots are the graph line and the letter a is before the dots so when this is posted the dots won't shift. The a's have nothing to do with the graphs.

Graph A.

aa.

aaaa.

aaaaaa.

aaaaaaaaaa.

aaaaaaaaaaaaaa.

aaaaaaaaaaaaaaaaaa.

aaaaaaaaaaaaaaaaaaaaaa.

aaaaaaaaaaaaaaaaaaaaaaaa.

aaaaaaaaaaaaaaaaaaaaaaaaaa.

aaaaaaaaaaaaaaaaaaaaaaaaaaaa.

Graph B versus time looks like this:

----------------------

aaaaaaaaaaaaaaaaaaaaaa|

aaaaaaaaaaaaaaaaaaaaaa|

aaaaaaaaaaaaaaaaaaaaaa|

Graph C versus time looks like this:

aaaaaaaa|-------------|

aaaaaaaa|aaaaaaaaaaaaa|__________

aaaaaaaa|

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For questions 1-3 use these graphs which represent a car traveling on a straight east west highway. East is the positive direction. At the start the car is traveling west at a constant 60 mph. When it reaches the town limits, it slows down to 30 mph and continues at that speed until it reaches the west end of town, at which point it speeds up quickly to 60 mph and maintains that speed.

1) Which graph best represent the velocity of the car as a function of time and why?

Graph A

Graph B

Graph C

none of them

2) Which graph best represnts the acceleration of the car as a function of time?

Graph A

Graph B

Graph C

none of them

3) Which graph best represents the position of the car as a function of time?

Graph A

Graph B

Graph C

none of them

4) What must a quantity have in order to be a vector? There could be more than one answer.

magnitude

a constant value

direction

a changing value

5) A boat propels itself relative to the river water at 3mph north. The river current is 4mph west. The magnitude of the boats velocity relative to te shore is

-1 mph

1 mph

5 mph

7 mph

none of these

#### Solution Preview

Note: I posted a document to show the graphs, and I will include explanations of them.

Solution:

Questions 1, 2 and 3. The graphs of motion. See attachment.

Physics explanations:

Note 1. We are free to establish that velocities to the west are positive, and velocities to the east would be negative.

Note 2. The initial constant velocity toward the west is V1= +60 mph until reaching the town limit.

Note 3. At the entering town limit the car begins to slow down to change its velocity to its ...