Download I will read the background information about Newton`s Second Law

Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Newton’s Second Law Lab
Content Objective: I will collect information on forces, masses and accelerations and use that data to create
an Acceleration vs. Force and Acceleration vs. Mass graphs. I will then analyze the graphs to determine the
relationship between each variable.
Language Objective: I will read the background information about Newton’s Second Law and discuss the prelab question with my lab group. I will write responses to reflection questions about the lab and write a general
rule that relates mass, force and acceleration.
Background Reading
How does a cart change its motion when you push and pull on it? You might think that the harder you push on a
cart, the faster it goes. Is the cart’s velocity related to the force you apply? Or does the force just change the
velocity? Also, what does the mass of the cart have to do with how the motion changes? We know that it takes
a much harder push to get a heavy cart moving than a lighter one.
A force sensor and an accelerometer will let you measure the force on a cart simultaneously with the cart’s
acceleration. The total mass of the cart is easy to vary by adding masses. Using these tools, you can determine
how the net force on the cart, its mass and its acceleration are related. This relationship is Newton’s Second Law
of Motion.
Pre Lab Questions
1. When you push on an object, how does the magnitude of the force affect its motion?
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A. If you push harder, is the change in motion smaller or larger?
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B. Do you think this is an inverse or direct relationship?
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2. Assume that you have a bowling ball and aa baseball, each suspended from a different rope. If you hit
each of these balls with a full swing of the baseball bat, which ball will change its motion by the greater
amount?
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3. In the absence of friction and other forces, if you exert a force, F, on a mass, M, the mass will accelerate.
If you exert the same force on a mass of 2m, would you expect the resulting acceleration to be twice as
large or half as large?
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A. Is this a direct or inverse relationship?
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Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Materials
Mass Set
Mass Hanger
Dynamics Track
1 m String
Dynamics Cart with Wireless Sensor
LabQuest 2
Procedure:
Setup of Equipment
1. Attach the dynamics track feet to the track and level the track.
a. To level the track, place a dynamics cart in the center and adjust the feet until it stays at rest.
2. Turn on the LabQuest 2 and the Wireless Dynamics System (WDSS).
3. Use the following steps to connect the WDSS to your LabQuest 2.
a. Tap “Sensor” at the top of the screen.
b. Tap “WDSS Setup” under the sensor menu.
c. Tap “Scan”
d. Select the Name of your Lab Groups Device. It is on the side of the WDSS
e. Tap “Force” and “Accel-X”
f. Tap “OK”
4. With the cart at rest on the track, use the following steps to “Zero” the sensor.
a. Tap “Sensor” at the top of the screen.
b. Tap “Zero” under the sensor menu.
c. Tap “All WDSS Sensors”
5. Tie one end of 1-meter-long string to the hook of the WDSS and the other end to the small blue mass
hanger.
6. Place a small piece of tape across the end of the track to help reduce friction.
7. Place the track so that the mass hanger will hang over the side of the table .
Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Procedure Continued
The effect of Net force on acceleration
1. Use the digital balance to determine the mass of the dynamics cart and wireless sensor. Record this
value above the data table.
2. Place a 50 g mass on the hanger, pull the cart back so that the mass is just below the edge of the table.
3. Go to the graph screen on the LabQuest 2.
4. Press the Play button on the lab quest and release the cart. Make sure to catch the cart before it
reaches the end of the track. Stop the data collection after stopping the cart. You should get two
graphs that look like the graphs below.
5.
The top graph represents the Net Force acting on the cart and the bottom graph represents the carts
acceleration. Use the TOP graph to identify the part of the experiment when the cart was only being
pulled by the hanging mass and no other forces.
After I stopped the
Cart
Before I let go of the Cart
When Only the Hanging
Mass acted on Cart
6. Highlight the middle region of the graph by dragging across that section.
7. Follow the steps below to find the Mean (average) Force and Mean Acceleration during the motion of
the cart.
a. Tap “Analyze” at the top of the screen.
b. Tap “Statistics” in the Analyze Menu.
c. Choose “Force.”
d. Repeat steps a and b but choose “X Acceleration”
e. Tap the Force box on the right side of the screen. A data list should come up on the screen.
Record the Mean Force in the Experiment 1 Data Table of the Lab. The select Ok.
f. Tap the X Acceleration box on the right side of the screen. Record the Mean Acceleration in the
Experiment 1 Data Table.
8. Repeat this experiment 2 more times using the 50 g mass.
9. Complete three more trials with a total of 100 g hanging over the side and 150 g.
Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Procedure Continued
The effect of Mass on Acceleration
1. Record the mass of the cart and sensor in the Experiment 2 Data Table.
2. Hang 200 grams on the mass hanger and CALCULATE the weight that will be pulling the cart. Record this
value above the Experiment 2 Data Table.
3. Like in the previous experiment, determine the mean acceleration of the cart and sensor when the 200 g
mass makes it accelerate. Record this value in the Experiment 2 Data table and repeat the procedure
for a total of 3 trials.
4. Measure the mass of your second dynamics cart. Determine the total mass of the system moved, when
the second cart is attached to the first using the Velcro strips. Record this value in the Experiment 2
Data Table.
5. Without changing the hanging mass, determine the acceleration of the two carts and sensor for three
different trials.
6. Add a 0.5 kg mass to the second cart and record the new total mass of the system that will be
accelerated. Record this value in Experiment Data Table 2.
7. Without changing the hanging mass, determine the acceleration of the two carts and sensor for three
different trials.
Data Table
Experiment 1: Forces effect on Acceleration
Mass of Cart & Sensor: _________________ Kilograms
Hanging
Mass
Trial 1
Mean Force (N)
Trial 2
Trial 3
Mean Acceleration (m/s2)
Trial 1
Trial 2
Trial 3
50 g
100 g
150 g
Experiment 2: Masses effect on Acceleration
Weight of Hanging Mass: _________________ Netwons
Objects being moved by
Hanging Weight
Cart & Sensors
2 Carts & Sensor
2 Carts, 0.5 kg mass and
Sensor.
Mass of Object (kg)
Mean Acceleration (m/s2)
Trial 1
Trial 2
Trial 3
Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Analysis
1.
Create a scatter plot graph to represent the data collected from each experiment.
Make sure you graph included the following.
a. Title, Labels axis with the units of measurement, a line of best fit and an appropriate scale on
the two axis.
Name: ________________________________
Checklist #5
Date: ________________________
Block: ___________
Conclusion
1. What is the relationship between Force and Acceleration when the mass of the object stays the same?
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2. What is the relationship between Mass and Acceleration when the net force acting on the object stays
the same?
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3. Use one of your graphs to predict how fast a 1.0 kg object would have accelerated when a 200 g mass
was hanging on the string?
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4. Three identical trucks were all stopped at a red light. One truck was pulling a trailer full of stone, the
second truck was pulling an empty trailer and the third truck was not pulling anything.
a. Which truck would have the greatest acceleration when the light turns green?
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b. Which truck would have the slowest acceleration when the light turns green?
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5. Mr. White challenges his three-year-old son to a race. Each of them need to push a shopping cart full of
water bottles across the parking lot to their car. To be fair, Mr. White makes sure both carts have the
same amount of mass.
a. Who will be able to make their shopping cart accelerate faster?
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b. Why?
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