Forces and Motion using PhET’s Force and Motion Basics HTML5
Part 2 – Motion and Part 3 - Friction
Go to my Google Classroom and click on the link to PhET Simulations. Click HTML5 Sims, and then Forces and Motion: Basics.
Part 2- Motion
1. Click the tab “Motion” (the 2nd acivity)
2. Check the boxes next to “ force, values, masses, and speed”
3. A box on the skateboard. Adjust the “Applied Forces” to 200N. The screen should look like this:
4. Watch (count to ten) and describe what happens? (Hint: look at the speedometer)
5. Click “reset” and repeat steps 2 and 3 with the refrigerator. What happens this time? How is it different than the box?
6. Click the “Reset All” button.
7. Experiment… Repeat steps 2-3 using different objects and/or people and different applied forces.
8. What happens to the speed as different objects/people are added?
What happens to the applied force as it increases/decreases?
9. Why do you think this happens?
10. How much time does it take for 1 crate, 2 crates, a refrigerator, the man, the girl, and the mystery object, with same applied force get to maximum speed? Maximum speed is reach when the hand on the speedometer cannot go any further. (Record your answers in table below.) Open a new browser and type in this link to use the stopwatch. (or you can use the stopwatch function on your phone or a clock) http://www.online-stopwatch.com/full-screen-stopwatch/Object / Mass / Applied force (Newtons) / Time (Use stopwatch)
1 crate / 300N
2 crates / 300N
Refrigerator / 300N
Man / 300N
Girl / 300N
Mystery Object / 300N
11. Do you think the object’s mass determines how long it will take for that object to reach maximum speed with an applied force of 300 N? Yes or No, Explain your answer.
12. How much do you think the mystery object weighs based on how long it took to reach maximum speed at 300N? (Yes, you CAN
determine its mass when you compare it
to the other objects in question #10.
1. Click the tab “Friction”
2. Check the boxes next to “ forces and speed”
3. Place the refrigerator on the screen. Adjust the “Applied Forces” to 500N. The screen should look like this:
4. What happened? ______Did the refrigerator move?______
5. Click the “Reset All” button.
6. Check the boxes next to “values and speed”
7. Place the refrigerator on the screen again. Adjust the “Applied Forces” to 500N. Now, slide the friction tab toward “None”.
8. What happens as you slide the fiction tab closer to “None”?
9. Click “Reset All”.
10. Check the boxes next to “values and speed”
11. Experiment…Place any object or person on the screen.
Adjust the “Applied Forces” to 500N. Slide the friction tab toward “None” or “Lots”. Try to stop the friction tab where the friction force arrow is between 100N and 200N. (You may need to try this a few times before you are able to get this as things change quickly.)
12. Complete the table. Fill in the missing values.Object / Applied Force (N) / Friction Force (N) / Sum of Forces (N)
Crate / 200 / 125
Man / 472 / 272
Refrigerator / 51 / 99
Girl / 363 / 100
Garbage Can / 500 / 375
*You can use the Friction Tab to help you check your answers.
13. Write the number sentence or equation used to calculate the sum of forces.
1. How does the force placed on an object affect how it moves?
2. What happens if there is too much friction? Will the object move slowly, fast or not at all?
3. What if only a little friction is added, how will the object move?