PHYSICS 112 San Francisco State University Lab 2 Motion in 1D Worksheet

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I need some help with PHYS 0112-01 General Physics I Motiopn in 1D. Please submit your answers as a PDF.

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Lab 2: Motion in 1 Dimension Physics 112 Open The Simulation: https://phet.colorado.edu/sims/cheerpj/moving-man/latest/movingman.html?simulation=moving-man This simulation works reliably on desktops and laptops, and should work for tablets (iPads) and other mobile devices. If your device has difficulty using this simulation, try reloading the simulation, and/or see your instructor for assistance. Part 1 1. Take about 5 minutes to explore the “Introduction” part of the simulation. You may want to: Click and drag the man to move him forward and backward. Observe what happens in the blue and red slider bars labeled position and velocity (you may ignore the green acceleration for now). Move him fast, move him slow, let him stay still. Move him both to the left and to the right. Use the “Reset All” button to start fresh. Click and drag the blue position slider bar to the left and right and see how the man responds. Report some of your observations below: 2. Click and drag the man to the tree. Using only the red velocity slider bar (that is, without touching the man or the blue position slider bar), make the man follow the story with the following stages: i- The man starts from rest by the tree, and then he moves toward the house walking with constant velocity… ii- Then, he slows down and ultimately comes to a stop… iii- And then stands still for a while…. iv- He then begins to move back towards the tree, moving slowly at first and then speeding up. For each of the four stages, describe how you adjusted the red velocity slider bar to get the man to follow the story. a. Stage i: b. Stage ii: c. Stage iii: d. Stage iv: © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Part 2: Single Stage Position-time and Velocity-time Graphs 1. START. Now, choose “Charts” from the top menu. Leave the position – time graph, and the velocity – time graph open, but close the acceleration-time graph using the red minus in the upper right corner. Your screen should look like this. 2. EXPLORE. Press PLAY, then click and drag the man to move him forward and backward. Observe what shows up on the graphs. Write or draw what you observe below: Notes on drawing graphs based on data: In the activities below, when asked to sketch a graph you observe, your sketch should focus on the overall shape of the graph and not the small fluctuations. For example, if the computer shows the graph on the left, we will assume that the value of the quantity is approximately constant, and sketch a horizontal line as shown in the graph at the right. Similarly, there is often motion displayed at the start of data collection that is not of interest. For example, you may start the data collection and then start the motion of interest a second or so later. In such a case, do not bother to sketch the meaningless portion of the graph. In general, if you have questions about what portions of a graph are important, check with your lab instructor. © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Graphs of motion with constant velocity 3) Starting from X=0 (at the center), move the man toward the house at constant speed. (Moving with a constant speed may take some practice!) (Note that you may have to change the scale on the graph.) A. With words, describe the shape of the position vs. time graph (during the time you were moving with constant speed) B. With words, describe the shape of the velocity vs. time graph (You may need to zoom in) C. If you have not already done so, sketch these graphs above. Use the vertical dotted lines to ensure that the time scales for the two graphs are consistent. Remember to sketch a smooth graph, ignoring the wiggles. Also, sketch only the motion of interest, i.e. when you were moving at constant velocity. Put approximate numbers on your axes. 4) Restarting from X=0, move the man toward from the house at constant speed; this time, move with a greater speed than you did in part 3 above. A. Describe the shape of the position vs. time and velocity vs. time graphs. B. If you have not already done so, sketch these graphs. 5) Compare the graphs for the motions in part 3 and part 4. A. How do the graphs of position vs. time compare? Note the differences as well as the similarities. B. How do the graphs of velocity vs. time compare? Note the differences as well as the similarities. © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 6) Now starting from the house, move the man away from the house toward the tree at constant speed. Try to move with the same speed that you did in part 3 above. A. Describe the shape of the position vs. time and velocity vs. time graphs (during motion of interest) If you have not already done so, sketch these graphs. B. What aspect of the position vs. time graph shows that you are moving toward the tree rather than away from it? Explain. C. What aspect of the velocity vs. time graph shows that you are moving toward the tree rather than away from it? Explain. Velocity is a vector quantity. A complete description of the velocity includes both magnitude and direction of motion. The magnitude of the velocity vector is called the speed of the object. In onedimensional motion, the direction of motion is indicated by the sign of the velocity. © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 7. Generalize your results from parts 3 through 6. A. Looking at a position vs. time graph for some object’s motion, how can you tell whether the object’s speed is constant? B. Looking at a velocity vs. time graph for some object’s motion, how can you tell whether the object’s speed is constant? C. Looking at a position vs. time graph for some object’s motion, how can you tell the direction of motion? D. Looking at a velocity vs. time graph for some object’s motion, how can you tell the direction of motion? E. Given the position vs. time graph for an object moving with uniform motion, what feature of the graph tells you the speed of the object? Is your answer consistent with the formula for velocity (i.e., v = Δx / Δt)? Explain. F. Given the velocity vs. time graph for an object moving with uniform motion, what feature of the graph tells you the speed of the object? © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Part 3: Calculating Velocity We use the time intervals as subscripts to indicate the time segment. For example: 7.0 Position (m) 1. Suppose this position – time graph to the right represents the Man’s motion, starting at 0.0 m. To draw the velocity – time graph, we need the slope (velocity) from 0 to 2 seconds. 𝑣⃗0−2𝑠 = velocity from 0 to 2 seconds -8.0 0 2 4 5 6 Time (s) We can calculate the velocity from a position-time plot by calculating the slope between two points. For example, for the first interval in the graph above, 𝑣0−2 Δ𝑥 (𝑥𝑡=2 − 𝑥𝑡=0 ) (− 8 − 0) 8 = = = = − = −4 Δ𝑡 (𝑡2 − 𝑡0 ) (2 − 0) 2 2. Following the formula in the dotted boxes, Determine the velocity values for intervals a, b, and c. Calculation of b. goes here: ⃗⃗𝟎−𝟐𝒔 =_ -4________ a. 𝒗 ⃗⃗𝟐−𝟓𝒔 = ___________ b. 𝒗 ⃗⃗𝟓−𝟖𝒔 = ___________ c. 𝒗 Calculation of c. goes here: © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 8 Velocity (m/s) 3. Now, sketch the velocity – time graph that matches the Man’s motion (on the right). Time (s) © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Part 4: Translating Between Representations In each of the following problems, one of the following descriptions of motion will be given: • a written description • a graph of position vs. time (x vs t) • a graph of velocity vs. time (v vs t) You and your partners should use the given description to determine the remaining descriptions of the motion. Do this first without using the simulation, based on your intuition and what you have learned so far. In your word descriptions, state the direction of motion, if any, and describe whether you will move with constant speed, increasing speed, or decreasing speed. Use the simulation to check your answers. If there are differences between your prediction and your final observation, show both graphs but make clear which is which (e.g., use different colors or patterns). You will learn more if you make predictions first and then examine the ways in which your predictions differ from your observations, if any. 1) Description of motion: 2) Description of motion: © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 3) Description of motion: Starting at a negative position and moving with constant positive speed. 4) Description of motion: © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Challenge Problems 5) (Note that the speed of this object is not constant.) Description of motion: A. What aspect of the x vs t graph shows that the speed is changing? B. What aspect of the v vs t graph shows that the speed is changing? 6) Description of motion: Starting at X=0, the man moves toward the house with decreasing speed, then just as he comes to rest, he begins to move away from the house with increasing speed. Describe the shape of the curve (i.e. is it straight? curved?, etc.) Make sure your answer is consistent with what you have said earlier. © 2021 San Francisco State University. Adapted from: Loeblein, King, and Forbes 2018; S.E. Kanim, M.E. Loverude, and L.G. Ortiz, 2005; Loeblein, 2013 Lab 2: Motion in 1 Dimension POST-LAB KNOWLEDGE CHECK Physics 112 Your Name: ____________________________ Lab Partners’ Names: ___________________________ Be sure to use your notes and responses from the lab you conducted to answer this problem. Check that your answers on are consistent with what you have learned in the lab. 1. A biologist is investigating the behavior of ants. The graph below shows the position of an ant as a function of time as the ant moves along a celery stalk. To describe the ant’s motion, a coordinate system is chosen such that x = 0 at the center of the stalk and positive values of x indicate positions on the leafy end of the stalk. (a) At what time or times, if any, is the ant at rest? Explain. (b) At what time or times, if any, is the ant moving toward the leafy end of the celery stalk? Explain. (c) At what time or times, if any, does the ant change direction? Explain. (d) At what time is the ant furthest from where it was at t = 0? Explain. (e) During what time intervals, if any, is the ant moving with approximately constant speed? Explain. (f) At what time is the ant moving fastest? Explain. © 2005 S.E. Kanim, M.E.Loverude, and L.G. Ortiz; San Francisco State University Lab 2: Descriptions of Motion SUMMARY Physics 112 (Look at your lab notes while doing this!) 1. Write down one major conclusion you can draw from this week’s laboratory. Please explain in detail. 2. Describe the experimental evidence that supports your conclusion. Please explain in detail. 3. Give one example of applications/situations for the finding(s) you described above in your (everyday) life outside of physics lab, and explain the connection. © 2021 San Francisco State University
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Explanation & Answer

Please see attached

Lab 2: Descriptions of Motion

SUMMARY

Physics 112
Your Name:
Lab Partners’ Names:
Be sure to use your notes and responses from the lab you conducted to answer this problem. Check that your answers on
are consistent with what you have learned in the lab.

1. A biologist is investigating the behavior of ants. The graph below shows the position of an ant as a function of
time as the ant moves along a celery stalk. To describe the ant’s motion, a coordinate system is chosen such
that x = 0 at the center of the stalk and positive values of x indicate positions on the leafy end of the stalk.

(a) At what time or times, if any, is the ant at rest? Explain.

The time at rest based on the above graph is seen to be: 2.5 seconds to 5.5 seconds

(b) At what time or times, if any, is the ant moving toward the leafy end of the celery stalk? Explain.

Since he moves towards the leafy stalk (positive end) when its path curve is moving upward. For this case,
biologist was moving to the leafy end at t= 5.5 s to 8 s.
(c) At what time or times, if any, does the ant change direction? Explain.

These are the points that are either PEAKS or TROUGHS. So it did change direction at t= 2.5 s and t=5.5 s
(d) At what time is the ant furthest from where it was at t = 0? Explain.

He is moving at a constant speed if it follows a fixed slope curve which should be any straight line. For this
case, he moves at a constant speed at t= 0 s to t=5.5 s.

(e) During what time intervals, if any, is the ant moving with approximately constant speed? Explain.

He will be moving fastest at the part of the curve with the highest absolute value of the slope or the one with
a slope (or tangent) which is almost a straight vertical line. For the curve of he's position, it must be moving
at its fastest at t=6 s to t = 8 s

© 2021 San Francisco State University

Lab 2: Descriptions of Motion

SUMMARY

Physics 112

(f)

At what time is the ant moving fastest? Explain.

He will have the same velocity if the slopes of their position curves are parallel. For their case he has same velocity
at t=4.5s to 5.5 s.

(Look at your lab notes while doing
this!)
1. Write down one major conclusion you can draw from this week’s laboratory. Please explain in
detail.

I learned that in one dimensional motion object motion is only in x direction but in 2dimension
motion object velocity both x direction ( horizontal ) and y direction ( vertical motion) .
2. Describe the experimental evidence that supports your conclusion. Please explain in detail.

The resultant motion is in between x and y axis, any object thrown with certain initial velocity
making some angle other than 90 with the horizontal and allowed to move under force of gravity
only is called projectile motion. Its vertical (final) velocity becomes zero; this reason gives the
object reach maximum height. But it has horizontal velocity so it not dropped at that it is moving
horizontal direction.
3. Give one example of applications/situations for the finding(s) you described above in your
(everyday) life outside of physics lab, and explain the connection.
Time of flight is just double the maximum height time.
It depends upon,
i) Speed at start -the faster, the further
ii) Elevation angle-45 degrees elevation angle gives the maximum height
iii) Wind velocity-If the wind is in the opposite direction of the motion of the projectile, the time
of flight decreases and if the wind is in the same direction as that of the projectile, the time of
flight increases.

© 2021 San Francisco State University

Ignore the word file, use only the two pdfs

Lab 2: Descriptions of Motion

SUMMARY

Physics 112
Your Name:
Lab Partners’ Names:
Be sure to use your notes and responses from the lab you conducted to answer this problem. Check that your answers on
are consistent with what you have learned in the lab.

1. A biologist is investigating the behavior of ants. The graph below shows the position of an ant as a function of
time as the ant moves along a celery stalk. To describe the ant’s motion, a coordinate system is chosen such
that x = 0 at the center of the stalk and positive values of x indicate positions on the leafy end of the stalk.

(a) At what time or times, if any, is the ant at rest? Explain.

The time at rest based on the above graph is seen to be: 2.5 seconds to 5.5 seconds

(b) At what time or times, if any, is the ant moving toward the leafy end of the celery stalk? Explain.

Since he moves towards the leafy stalk (positive end) when its ...


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