# 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|

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Graph C versus time looks like this:

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

aaaaaaaa|aaaaaaaaaaaaa|__________

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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

https://brainmass.com/physics/velocity-time-graphs/solve-velocity-and-vectors-24178

#### 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 ...

Physics: Density, Vectors, Speed, Acceleration, Velocity

See attached file for proper formatting.

1.7. Which of the following equations are dimensionally correct? (a) vf = vi + ax

(b) y = (2 m)cos(kx), where k = 2 m-1.

1.26. The radius of a solid sphere is measured to be (6.50 ± 0.20) cm, and its mass is measured to be (1.85 ± 0.02) kg. Determine the density of the sphere in kilograms per cubic meter and the uncertainty in the density.

1. 44. Vector has x and y components of -8.70 cm and 15.0 cm, respectively; vector has x and y components of 13.2 cm and -6.60 cm, respectively. If, what are the components of ?

2. 12. An object moves along the x axis according to the equation x(t) = (3.00t2 - 2.00t + 3.00) m, where t is in seconds. Determine (a) the average speed between t = 2.00 s and t = 3.00 s, (b) the instantaneous speed at t = 2.00 s and at t = 3.00 s, (c) the average acceleration between t = 2.00 s and t = 3.00 s, and (d) the instantaneous acceleration at t = 2.00 s and t = 3.00 s.

2. 25. A truck on a straight road starts from rest, accelerating at 2.00 m/s2 until it reaches a speed of 20.0 m/s. Then the truck travels for 20.0 s at constant speed until the brakes are applied, stopping the truck in a uniform manner in an additional 5.00 s. (a) How long is the truck in motion? (b) What is the average velocity of the truck for the motion described?

2. 55. A rock is dropped from rest into a well. The sound of the splash is heard 2.40 s after the rock is released from rest. How far below the top of the well is the surface of the water? The speed of sound in air (at the ambient temperature) is 336 m/s.

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