Your text here
Name: ____________________________________ Table: _____________ Section: __________
Lab 4: PhET Simulation – Friction
PhET simulations are simulations on all sorts of topics (not just physics) that come
from the University of Colorado - Boulder
To find the simulation, either Google “Phet simulation ramp forces and motion” or go
directly to this link: http://phet.colorado.edu/en/simulation/ramp-forces-and-motion
Click “Run Now.” When the simulation opens:
• Click on the “Force Graphs” tab at the top.
• Set the ramp angle to zero degrees.
• Check the check boxes for the applied force and the force of friction at the bottom left.
We are going to examine the way friction behaves when you push an object on a flat
surface. You can make the wooden stick-figure doll apply a force to the crate by clicking on
the crate and dragging it along, or just slide the “Applied Force “ slider up or down.
Introduction: Starting with the crate stationary, slowly increase the applied force on the
crate without having the crate move quite yet. What is the acceleration? How does the
frictional force compare to the applied force?
Acceleration when velocity changes, the rate of change.
Frictional force is equal to the applied force but its acting the opposite direction.
Do Fapplied and Ffriction (labeled Fa and Ff) constitute a Newton’s third law pair? Why or why
not?
No they do not constitute to Newtons third law pair because its not an action reaction.
Clear the scenario using the button at the bottom and now gradually increase the applied
force until the block starts to move. At approximately what value of applied force does the
block begin to move?
At 493 Newtons
Describe in words what happens to the frictional force the instant the block begins moving.
(Use specific evidence from the free-body diagram and/or the graph provided by the
simulation.)
The frictional force is pushing back instantly on the box. As the applied force pushes
forward the frictional force pushes back.
Boston University Studio Physics – Phet Friction Exploration
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, Click on the “Friction” tab at the top. Again, set the ramp angle to zero degrees.
Now double the mass of the crate using the appropriate slider or entering the value. Predict
the value of the applied force necessary to get the crate moving.
493 N
Apply the force. What is the actual value needed to move the block? How does it compare to
your prediction?
The actual value was 500 N, I was really close to the number.
With the doubled mass, change to a different acceleration due to gravity, such as that on the
Moon or on Jupiter. Enter the new value of g here: ___24.7m/s^2________
Again, make a prediction of the value of the applied force necessary to get the crate moving.
1000N
What is the actual value needed to move the block? How does it compare to your
prediction?
Its 900N, my prediction was that it was going to be DOUBLE than before.
Let’s state the two important things about friction you have verified:
A. Friction behaves differently depending on whether an object is moving or stationary.
We call these different scenarios __static__ and ___Kinetic_________ friction,
respectively.
B. Heavier objects experience __more____ friction!
Kinetic Friction:
Click on the “Force graphs” tab at the top of the window, and set the ramp angle to 30°.
Boston University Studio Physics – Phet Friction Exploration
This study source was downloaded by 100000841689952 from CourseHero.com on 06-14-2022 01:47:15 GMT -05:00
page 2
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Name: ____________________________________ Table: _____________ Section: __________
Lab 4: PhET Simulation – Friction
PhET simulations are simulations on all sorts of topics (not just physics) that come
from the University of Colorado - Boulder
To find the simulation, either Google “Phet simulation ramp forces and motion” or go
directly to this link: http://phet.colorado.edu/en/simulation/ramp-forces-and-motion
Click “Run Now.” When the simulation opens:
• Click on the “Force Graphs” tab at the top.
• Set the ramp angle to zero degrees.
• Check the check boxes for the applied force and the force of friction at the bottom left.
We are going to examine the way friction behaves when you push an object on a flat
surface. You can make the wooden stick-figure doll apply a force to the crate by clicking on
the crate and dragging it along, or just slide the “Applied Force “ slider up or down.
Introduction: Starting with the crate stationary, slowly increase the applied force on the
crate without having the crate move quite yet. What is the acceleration? How does the
frictional force compare to the applied force?
Acceleration when velocity changes, the rate of change.
Frictional force is equal to the applied force but its acting the opposite direction.
Do Fapplied and Ffriction (labeled Fa and Ff) constitute a Newton’s third law pair? Why or why
not?
No they do not constitute to Newtons third law pair because its not an action reaction.
Clear the scenario using the button at the bottom and now gradually increase the applied
force until the block starts to move. At approximately what value of applied force does the
block begin to move?
At 493 Newtons
Describe in words what happens to the frictional force the instant the block begins moving.
(Use specific evidence from the free-body diagram and/or the graph provided by the
simulation.)
The frictional force is pushing back instantly on the box. As the applied force pushes
forward the frictional force pushes back.
Boston University Studio Physics – Phet Friction Exploration
This study source was downloaded by 100000841689952 from CourseHero.com on 06-14-2022 01:47:15 GMT -05:00
page 1
https://www.coursehero.com/file/64614568/LAB-Friction-Phet-2pdf/
, Click on the “Friction” tab at the top. Again, set the ramp angle to zero degrees.
Now double the mass of the crate using the appropriate slider or entering the value. Predict
the value of the applied force necessary to get the crate moving.
493 N
Apply the force. What is the actual value needed to move the block? How does it compare to
your prediction?
The actual value was 500 N, I was really close to the number.
With the doubled mass, change to a different acceleration due to gravity, such as that on the
Moon or on Jupiter. Enter the new value of g here: ___24.7m/s^2________
Again, make a prediction of the value of the applied force necessary to get the crate moving.
1000N
What is the actual value needed to move the block? How does it compare to your
prediction?
Its 900N, my prediction was that it was going to be DOUBLE than before.
Let’s state the two important things about friction you have verified:
A. Friction behaves differently depending on whether an object is moving or stationary.
We call these different scenarios __static__ and ___Kinetic_________ friction,
respectively.
B. Heavier objects experience __more____ friction!
Kinetic Friction:
Click on the “Force graphs” tab at the top of the window, and set the ramp angle to 30°.
Boston University Studio Physics – Phet Friction Exploration
This study source was downloaded by 100000841689952 from CourseHero.com on 06-14-2022 01:47:15 GMT -05:00
page 2
https://www.coursehero.com/file/64614568/LAB-Friction-Phet-2pdf/
