NEWTON LAWS SIMULATION
1 – Force, Mass, Acceleration
Open the simulation (https://phet.colorado.edu/en/simulation/forces-and-motion-basics) and select
Acceleration.
Select Acceleration. Set the Friction to None (and make sure re-set it to zero for each run). Click and drag the
person toward the wooden box to apply a force on it. You can select to display a physical quantity using the
table on the top right corner. Answer the following questions
1. As you apply a constant force, what happens to the speed?
2. Now to maintain a constant speed what should you do?
3. When you decrease the applied force what happens to acceleration?
Set the applied force to a fix value.
4. Take 50 kg mass and note the value of acceleration. Now, double the mass by adding a
second wooden box on top, what happens to acceleration?
5. Take 200 kg mass and note the acceleration. Now decrease the mass by factor of two, what
happens to acceleration.
6. From the above-mentioned simulation state the relationship between mass and acceleration for
constant applied force.
7. With the friction set to zero, does the object need a force for it to move at constant speed?
2 – Mystery Mass
Use the same simulation but now select Motion.
There is no friction and your goal is to find mass of the yellow present with the red ribbon. The
value of the acceleration is not given so you’ll have to find another way to estimate the
acceleration. Hint: you can use the kinematic equations and take measurements of time intervals with
a stopwatch (your phone for example).
8. What is the mass of the present?
3 – Data Analysis
An experiment is conducted by using a force sensor and cart system. Different forces are
applied on a cart and the accelerations are measured as shown in table below.
Force (N) 9.6 14.8 20.0 24.5 33.6 35.6 43.0 49.7
Acceleration (m/s2
) 2 3 4 5 6 7 8 9
Make a plot of force vs acceleration (do not set the 0 intercept).
9. Is the graph quadratic?
10. What physical quantity does the slope represent?
11. What is the value of slope?
4– Action/Reaction pairs
Open the simulation (https://phet.colorado.edu/en/simulation/forces-and-motion-basics) and select
Friction.
You will study the force of friction more in details in the next online simulation, right now we are not
interested on its quantitative aspects, just how the friction relates to the other forces.
Apply a force of 50 N
12. Does the box move?
13. Which force corresponds to the reaction of the horizontal normal force acting on the person?
14. Which force corresponds to the reaction of the vertical normal force acting on the ground?
15. Which force corresponds to the reaction of the friction acting on the ground from the box