CONSTANT VELOCITY

Using what you learned from the buggy lab, define the following terms as we use them in physics.

position:

velocity:

speed:

time:

Accelerated Physics Constant Velocity — Page 1 of 8

_____________________________________ __________________ ________Name Date Period

PART A1. A lady bug and a turtle are confined to move on a number line. You observe the lady bug and turtle for five

complete seconds. The figure below shows images of lady bug and turtle taken each second.

2. Record the data in the tables below.

LADY BUGLADY BUG TURTLETURTLE

time (s) position (m) time (s) position (m)

0 s – 5 m 0 s – 5 m

1 s 1 s

2 s 2 s

3 s 3 s

4 s 4 s

5 s 5 s

3. Plot position vs. time for the lady bug and the turtle on the same graph (using different colors).

Accelerated Physics Constant Velocity — Page 2 of 8

! –6 m! ! –4 m! ! –2 m! ! 0! ! +2 m! ! +4 m! ! +6 m

t = 0 s

t = 0 s

+ 6

+ 4

+ 2

0

– 2

– 4

– 6

x (m)

t (s)1 2 3 4 5

4. Describe the graph in words. What are the similarities in and differences between the two graphs? What does this tell you about the similarities in and differences between the way the lady bug and turtle move?

5. Calculate the slope of the lady bug's line and the turtle's line (with units). LADY BUG: TURTLE:

6. Write the equation of each line (in slope-intercept form) using the variables we care about (position and time). LADY BUG: TURTLE:

7. If the lady bug and turtle continue moving like this . . .

(a) use your equation to determine where they will be 7.5 seconds after they started moving. LADY BUG: TURTLE:

(b) how far will they have traveled in the 7.5 seconds since they started moving? LADY BUG: TURTLE:

8. Plot a graph of velocity vs. time for the lady bug and the turtle on the same graph (using different colors).

Accelerated Physics Constant Velocity — Page 3 of 8

+ 3

+ 2

+ 1

0

– 1

– 2

– 3

v (m/s)

t (s)1 2 43 5

PART B1. Again, you observe the lady bug and turtle for five complete seconds. The figure below shows images of

lady bug and turtle taken each second.

2. Record the data in the tables below.

LADY BUGLADY BUG TURTLETURTLE

time (s) position (m) time (s) position (m)

0 s – 6 m 0 s + 3 m

1 s 1 s

2 s 2 s

3 s 3 s

4 s 4 s

5 s 5 s

3. Plot position vs. time for the lady bug and the turtle on the same graph (using different colors).

Accelerated Physics Constant Velocity — Page 4 of 8

+ 6

+ 4

+ 2

0

– 2

– 4

– 6

x (m)

t (s)1 2 3 4 5

! –6 m! ! –4 m! ! –2 m! ! 0! ! +2 m! ! +4 m! ! +6 m

t = 0 s

t = 0 s

4. Describe the graph in words. What are the similarities in and differences between the two graphs? What does this tell you about the similarities in and differences between the way the lady bug and turtle move?

5. Calculate the slope of the lady bug's line and the turtle's line (with units). LADY BUG: TURTLE:

6. Write the equation of each line (in slope-intercept form) using the variables we care about (position and time). LADY BUG: TURTLE:

7. If the lady bug and turtle continue moving like this . . .

(a) use your equation to determine where they will be 12 seconds after they started moving. LADY BUG: TURTLE:

(b) how far will they have traveled in the 12 seconds since they started moving? LADY BUG: TURTLE:

8. Plot a graph of velocity vs. time for the lady bug and the turtle on the same graph (using different colors).

Accelerated Physics Constant Velocity — Page 5 of 8

+ 3

+ 2

+ 1

0

– 1

– 2

– 3

v (m/s)

t (s)1 2 43 5

PART C1. Lady bugs and turtles can move in ways that are even more interesting! The figure shows what is called a

dot diagram. A dot diagram is not all that different from the diagrams of the lady bug and turtle we saw before. Rather than seeing images of the same object taken every second, we replace the object with a simple dot (thus the name "dot" diagram). Here, we'll look at the turtle only.

2. The data is recorded in the table below.

time (s) position (m)

0 s + 2 m

1 s + 3 m

2 s + 4 m

3 s + 5 m

4 s + 6 m

5 s + 6 m

6 s + 6 m

7 s + 3 m

8 s 0 m

9 s – 3 m

3. Based on the dot diagram and the data table, describe the motion of the turtle in words.

Accelerated Physics Constant Velocity — Page 6 of 8

! –6 m! ! –4 m! ! –2 m! ! 0! ! +2 m! ! +4 m! ! +6 m

t = 0 s

4. Plot the graph of position vs. time for the the turtle.

5. Describe the graph in words. What does the graph tell you about the turtle's motion?

6. Calculate the slope (with units) of each segment of the turtle's motion.

7. Use your results from #6 to plot a graph of velocity vs. time for the turtle.

Accelerated Physics Constant Velocity — Page 7 of 8

+ 3

+ 2

+ 1

0

– 1

– 2

– 3

v (m/s)

t (s)1 2 743 5 8 96

+ 6

+ 4

+ 2

0

– 2

– 4

– 6

x (m)

t (s)1 2 743 5 8 96

8. In physics, it's useful to differentiate between an object's displacement and the distance it travels.

• Displacement tells you where an object is relative to its starting point. This includes direction!

• Distance tells you how many meters (or kilometers, inches, furlongs, etc.) the object actually traveled.

For example, if you hit a home run and run around the bases, as you return to home plate your displacement is zero but your distance traveled is 360 feet.

(a) What is the turtle's displacement over the 9-second time interval? Hint: Your answer should include both magnitude (how far?) and direction (which way?).

(b) What distance did the turtle travel in the 9-second time interval?

SUMMARIZEHow are graphs of position vs. time and velocity vs. time related?

APPLYHere we're only going to look at shapes (not specific numbers). Given the position vs. time graph on the left, sketch a corresponding velocity vs. time graph.

Accelerated Physics Constant Velocity — Page 8 of 8

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