Newton’s Second Law
012-11003 r1.04
Newton’s Second Law
Introduction
Journals and Snapshots
The Snapshot button is used to capture the
screen.
The Journal is where snapshots are stored
and viewed.
The Share button is used to export
or print your journal to turn in your
work.
Each page of this lab that
contains the symbol
should be inserted into your
journal. After completing a
lab page with the snapshot
symbol, tap
(in the upper
right corner) to insert the
page into your journal.
Note: You may want to take a
snapshot of the first page of
this lab as a cover page for
your journal.
Newton’s Second Law
Lab Challenge
What is the relationship
between the net force
applied to an object and its
motion?
Newton’s Second Law
Background
Fk
Spring
x0 = 0
Mass
In Equilibrium
Fg
Like Newton, we will observe a simple system
to look for a relationship between net force
and motion. From earlier studies we know
that a mass hung from a spring experiences a
force due to gravity and a restoring force from
the spring. In equilibrium the two forces are
equal and opposite. When the mass is
displaced one of the two forces is greater,
thus causing a non-zero net force pointed
towards the equilibrium position. We will
investigate how this net force is related to the
motion of the system.
Newton’s Second Law
a)
Q1: In the box below,
indicate which force is
greater (spring or gravity)
for both a) and b), then
snapshot this page.
b)
∆x1
x0
x0
∆x2
Newton’s Second Law
Materials and Equipment
Collect all of these materials
before beginning the lab.
• Force Sensor
• Motion Sensor
• Springs
• Rod Stand
• Rod
• Mass
• Clamp
Newton’s Second Law
Sequencing Challenge
A. Oscillate the
mass on the
spring, and begin
collecting data.
B. Plot net force
measured by the
force sensor versus
acceleration.
C. Use the linear
curve fit to
determine the
slope of the line.
D. Connect the
Motion Sensor and
the Force Sensor to
the SPARK Science
Learning System.
The steps to the left are part
of the procedure for this lab
activity. They are not in the
right order. Determine the
correct sequence of the
steps, then take a snapshot
of this page.
Newton’s Second Law
Setup
1. Connect the Force Sensor to the rod and rod
stand.
2. Hang the mass from the Force Sensor using
the spring.
3. Place the Motion Sensor directly below the
mass with the face of the sensor pointed up at the
mass.
4. Connect the Force and Motion Sensor to your
SPARK Science Learning System.
Newton’s Second Law
Collect Data
1. With the mass hanging
motionless, press the
ZERO button on the force
sensor.
2. Pull down gently on the
mass and release to start
it moving up and down.
3. Tap
data.
to start collecting
4. After the mass has
finished three to four
complete cycles (~5 to 10
seconds), tap
to
stop data collection.
Newton’s Second Law
Analysis
1. Why do you think it is important to press the
ZERO button before collecting data?
a) to calibrate the Force Sensor
b) to ensure the Force and Motion Sensor
both start from the same point
c) to make sure no forces are present
d) to ensure the Force Sensor is measuring
the net force on the mass
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Analysis
While collecting data we observed the position of
the object as it changed over time to ensure that
enough data was collected and that the data and
observed motion were consistent.
Next we will compare force to motion. After each
pair of graphs there is a question, you can go back
to the graph if you need to compare a few points
In time on each pair of graphs to determine the
nature of their relationship.
Newton’s Second Law
Newton’s Second Law
Analysis
2. Which description below best describes the
relationship between force and position in the case
of a spring and mass system?
a) Force is proportional to position.
b) Force is inversely proportional to position.
c) Force is unrelated to position.
d) Force is negatively proportional to position.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Newton’s Second Law
Analysis
3. Which description below best describes the
relationship between force and velocity?
a) Force is proportional to velocity.
b) Force is inversely proportional to velocity.
c) Force is offset from velocity.
d) Force is negatively proportional velocity.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Newton’s Second Law
Analysis
4. Which description below best describes the
relationship between force and acceleration?
a) Force is proportional to acceleration.
b) Force is inversely proportional to
acceleration.
c) Force is the inverse square of
acceleration.
d) Force is negatively proportional to
acceleration.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Analysis
During data collection we observed the position
of the object as it changed over time to ensure
that enough data was collected and that the
data and observed motion were consistent.
On the following graph we will plot force versus
acceleration to better understand the nature of
the relationship between these two variables.
Newton’s Second Law
Analysis
5. In the space below,
describe the shape of the
data plot of force versus
acceleration. Then take a
snapshot of this page.
Newton’s Second Law
Analysis
6. Apply a linear curve fit to
the force versus
acceleration plot, then take
a snapshot of this page.
*To Apply a Curve Fit:
1. Tap
to open the tool
palette.
2. Tap
to open the Curve
Fit screen.
3. Tap the name of the curve
fit required.
Newton’s Second Law
Analysis
7. Indicate any relationship that the slope of the curve fit line from the previous
page has with the experiment, and then take a snapshot of this page.
Newton’s Second Law
Analysis
8. Using your knowledge of graphing, how would you express the equation of the
line from the Force versus Acceleration graph in terms of the variables of this
experiment? Below the equation write out the units of each variable to be sure
the equation is balanced.
Newton’s Second Law
Synthesis
1. The harder a ball is thrown (apply more force), the faster it will move
(greater initial velocity resulting from acceleration). If you throw a 1 kg
softball as hard as you can and it is traveling at 20 m/s when it leaves your
hand, how fast will a 5 kg shot put travel with the same throw?
Newton’s Second Law
Synthesis
2. Force is proportional to acceleration. Given the answer to Synthesis
question 1, how would you describe the relationship between acceleration
and mass?
Newton’s Second Law
Synthesis
3. If we launch a rocket that has been designed to produce a constant force, will
the acceleration at initial launch be the same as the acceleration just before
the fuel is completely expended?
Newton’s Second Law
Synthesis
4. A similar experiment is set up so that a force sensor is used to drag a 1.5 kg
brick across a table while a motion sensor measures its acceleration. Several
trials are conducted, but the slope of the force versus acceleration graph is
consistently about 2. What would explain the difference? What would you
do to improve the results?
Newton’s Second Law
Multiple Choice Question
1. If two potatoes are launched from a potato
launcher that applies the same force,
a) the heavier potato will be traveling faster than
the lighter one.
b) the lighter potato will be traveling faster than
the heavier one.
c) regardless of their mass, they will be traveling
at the same velocity.
d) there is not enough information to draw a
conclusion.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Multiple Choice Question
2. A roller coaster is designed to deliver 3g of
acceleration at the bottom of a loop. The mass of
the cart is 500 kg and the rider is 100 kg. If the
track is designed to withstand 15,000 N of force
without buckling, will the cart and rider make it
through the loop?
a) No, this ride will likely end in disaster.
b) Yes, the cart and rider will easily make it past
the dip.
c) Yes, but a second rider of equal size would not
make it through.
d) There is not enough information to draw a
conclusion.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Multiple Choice Question
3. A 1000 kg rocket is launching with its engine
producing a force of 39240 N. What is its
acceleration?
a) 9.81 m/s2
b) 39.24 m/s2
c) 1000 m/s2
d) 29.43 m/s2
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Multiple Choice Question
4. The acceleration of an object is ___________
a) proportional to the mass of the object and the
force being applied.
b) proportional to the mass of the object, and
inversely proportional to the force being
applied.
c) proportional to the net force being applied and
inversely proportional to the mass of the
object.
d) always perpendicular to the force of gravity.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Multiple Choice Question
5. The net force on an object is ______________
a) proportional to the force of gravity.
b) the vector sum of the individual forces acting
on the object.
c) always balanced by the normal force.
d) both A and C.
Make your selection below
then take a snapshot of this
page.
Newton’s Second Law
Congratulations!
You have completed the lab.
Please remember to follow your teacher's instructions for cleaning-up and submitting
your lab.
Physics Template
References
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