11th Grade Physics Lab. Course Instructions: Follow the instructions on the lab sheet. Complete all parts of the lab and write your answers and results on the lab sheet. Lab sheet and rubric attached.Need returned today if possible.
lab_4c__2f__investigating_projectile_motion.pdf

lab_4c_rubric.pdf

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TEKS
Name ___________________________ Class ________ Date ___________
Physics
Lab Investigation 4C, 2F
TEKS 4C Analyze and describe accelerated motion in two dimensions
using equations, including projectile and circular examples. TEKS 2H Make
measurements with accuracy and precision and record data using scientific notation
and International System (SI) units. (Also TEKS 2F, 2K, 3A)
Comparative
Lab 4C, 2F: Investigating Projectile Motion
Background Information
Free fall is the movement of an object toward Earth because of gravity. An object that is in free fall
experiences acceleration. Acceleration is the rate at which velocity changes. Acceleration occurs when
there is a change in speed, change in direction, or both. During free fall, speed increases at a constant rate.
But what happens when an object also moves horizontally as it falls? The curved path that results is
known as projectile motion. Do you think an object’s horizontal motion will affect its fall?
In this investigation, you will compare the fall of two identical objects from the same height. The first
object will fall straight down. The second object will be given an initial horizontal velocity at the start of
its fall. You will determine how the horizontal motion of the second object affects the time it takes to fall.
Problem
What effect does horizontal motion have on the time an object takes to fall?
Pre-Lab Discussion
Read the entire investigation. Then, work with a partner to answer the following questions.
1. Controlling Variables Identify the manipulated, responding, and controlled variables in this
investigation.
a. Manipulated variables ___________________________________________________________
_______________________________________________________________________________
b. Responding variable ___________________________________________________________________
_______________________________________________________________________________
c. Controlled variable ____________________________________________________________________
_______________________________________________________________________________
1
TEKS
Name ___________________________ Class ________ Date ___________
Physics
Lab Investigation 4C, 2F
2. Formulating Hypotheses State a hypothesis about the effect of horizontal
motion on the time an object takes to fall.
_____________________________________________________________
Comparative
________________________________________________________________________________________
3. Predicting Make a prediction about the result of this investigation. Will one object fall more
quickly than the other, or will both objects hit the floor at the same time?
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
4. Controlling Variables Why are you told to let one object fall through a hole in the box, instead of
rolling the object off the edge of the table?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
5. Calculating How will you determine the average time for the five trials?
________________________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
6. Measuring Why do you think you will need a stopwatch that can measure tenths of a second?
________________________________________________________________________________________
________________________________________________________________________________________
2
Name ___________________________ Class ________ Date ___________
TEKS
Physics
Lab Investigation 4C, 2F
Materials (per group)
• 2 small spherical objects
• stopwatch (that can measure tenths of a
second)
• meter stick
• masking tape
• trajectory apparatus (for Going Further)
• carbon paper (for
Going Further)
• white craft
paper(for Going
Further)
Comparative
Safety
Put on safety goggles. Keep your hands and feet out of the path of falling objects. Note all safety alert
symbols next to the steps in the Procedure and review the meaning of each symbol.
Procedure
Part A: Timing Free Fall
1. Work with a classmate. Hold the object over the floor so that its bottom is in line with the top of the
table, as shown in Figure 1. Have your classmate check that the object is being held at the correct
height.
Figure 1
2. Position your classmate so that he or she can have a clear view of the object and the floor below.
Have your classmate be prepared to start the stopwatch.
3. Count down from five and release the object when you reach zero. Have your classmate begin the
stopwatch as soon as he or she sees you release the object. Your classmate will use the stopwatch to
measure the time it takes the object to hit the floor. Record this time in the data table.
4. Repeat Step 3 four more times. To calculate the average time that the sphere takes to reach the floor,
add all five times together, then divide the total by 5. Record this value in the data table.
3
TEKS
Name ___________________________ Class ________ Date ___________
Physics
Lab Investigation 4C, 2F
5. Using the meter stick, measure and place a piece of masking tape on the
floor 1 meter from the point directly under the edge of the tabletop, as
shown in Figure 2.
Comparative
Figure 2
6. Place the object to be dropped near the edge of the tabletop. Push the object off the table with just
enough force so that it lands on or close to the tape. CAUTION: To avoid hurting anyone, be careful
not to push the object too hard. Practice pushing the object off the table until you can make it land
on or close to the tape nearly every time.
7. Repeat Step 6 one more time and have your classmate use the stopwatch to measure the time the
object takes to fall to the floor. Record this time in the data table.
8. Repeat Step 7 four more times. To calculate the average time the object takes to fall to the floor, add
all five times together and then divide the total by 5. Record this value in the data table.
Part B: Comparing Free Fall
9. Hold one of the objects above the floor and in line with the top of the table, as in Step 1. Have your
classmate roll a second object toward the edge of the table. When you see the rolling object fall off
the edge of the table, release the object you are holding. Watch and listen to observe whether one
object hits the floor before the other.
10. Repeat Step 9 four more times. Record your observations in the space provided for results of Part B
below the data table.
Observations
Data Table
Trial
Vertical Fall
Fall With Horizontal Motion
Time (seconds)
Time (seconds)
1
4
Name ___________________________ Class ________ Date ___________
TEKS
Physics
Lab Investigation 4C, 2F
2
3
4
Comparative
5
TOTAL
Average
5
Name ___________________________ Class ________ Date ___________
TEKS
Physics
Lab Investigation 4C, 2F
Results of Part B
Comparative
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________
6
TEKS
Name ___________________________ Class ________ Date ___________
Physics
Lab Investigation 4C, 2F
Analysis and Conclusions
1. Calculating What was the average time required for the object dropped
straight down to hit the floor?
Comparative
_____________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
2. Calculating What was the average time the object with the initial horizontal velocity took to hit the
floor?
_______________________________________________________________________________
_______________________________________________________________________________
3. Analyze In Part B, did one sphere hit the floor before the other or did both spheres land at the same
time? Analyze what that says about the vertical component of projectile motion.
_______________________________________________________________________________
_______________________________________________________________________________
4. Evaluating and Revising Did your data support or contradict your hypothesis? Explain your
answer.
_______________________________________________________________________________
_______________________________________________________________________________
Going Further
The greater an object’s mass, the stronger is the force of gravity on the object. Does this mean that more
massive objects fall more quickly than less massive objects? What if they are projectiles? Design an
experiment to answer this question. Write a detailed plan for your experiment. Use the trajectory
apparatus to send projectiles and the carbon paper on top of white craft paper to mark where the
projectiles have landed. Describe the procedures you will use and identify all the variables involved.
Show your plan to your teacher. If your teacher approves, carry out your experiment.
7
Physics Hands-on Lab Rubric
Top Scores (16–20) – The top scoring students will do the following:
• Present ideas for a laboratory experiment that would accurately measure principles studied in this laboratory
• Develop reasonable hypothesis regarding the variables measured in this laboratory
• Accurately record data in well-organized and appropriately labeled data tables, as appropriate
• Graph data in appropriate graphs using all the proper conventions and labeling procedures
• Analyze data to show a deep understanding of physical principles
• Draw conclusions based on experiments that show how physical concepts affect the world around them
Middle Scores (10–15) – Acceptable scores for students go to those who do the following:
• Present ideas for laboratory experiment that would measure principles studied in this laboratory, although the
experiment may not actually work or measurements may be inaccurate
• Develop hypothesis about variables measured in this laboratory, although hypothesis may be unreasonable
• Record data in organized tables, as appropriate
• Graph data in graphs, but may have some errors in labeling or organization
• Analyze data with a basic understanding of physical principles
• Draw conclusions based on experiments using direction from questions posed in lab
Low Scores (0–9) – Students score poorly when they:
• Do not present ideas for laboratory experiment that would measure principles studied in this lab or these ideas
• Do not present hypothesis about values measured in this experiment
• Record data in tables in a disorganized manner
• Create graphs that do not correctly reflect the data and are difficult to interpret
• Incorrectly relate experiments to physical concepts

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