Content.njctl.org



Forces and Friction Simulation Lab Name___________________________8th Grade PSI Score _________/ 37 pointsIntroductionToday we will learn about how the motion of an object depends on the force exerted on it and its mass. We will look at scenarios where there is friction and scenarios where there is no friction. Click this link: This is a screen shot of the website: Click the “play” button (arrow) in the middle of the screen. Then click on the “Net Force” Thumbnail. The screen will look like this: Record all answers on this document. You will have to switch between the document and the forces and motion simulation in order to complete all parts of the activity. ExplorePlace a person on each side of the rope.Hit the “go” button to start the tug of war. Hit the “Return” button to stop the tug of war. Try it again with either the same amount of people on each side or a different amount of people on each side.Hit the “Reset” button in the top right corner. Click the boxes next to “sum of forces” and “values.” Continue experimenting putting people on each side using the controls described above. Use the simulation to answer the questions below.Questions (answer each question in the space provided)How can you make the blue side win?How can you make the red side win?How can you get a tie?Use the simulation to help you come up with a number sentence or equation we can use to find the sum of the forces.Here are a few suggestions. Fblue, - Fred Fblue + FredIf there was only one man pulling the cart what would the sum of forces be? Investigate: Part I- Mass and MotionMaterialsMotion SimulationOnline Stop watch Simulation PracticeClick the “Motion” thumbnail on the bottom.Check the boxes next to “force, values, masses, and speed”Use the black arrows at the bottom to change the “Applied Force” to 200N: Observe what happens (look at the speedometer). Note that the maximum speed is reached when the hand on the speedometer cannot go any further.Repeat steps 3 and 4 with the refrigerator (look at the speedometer). Click the “Reset” button to clear everything. Continue playing with the simulation until you feel comfortable understanding how to change objects, how to change the “Applied Force”, what the force/values/masses and speed show you, etc. Once you feel comfortable with this, you are ready to plan your own investigation!Plan and Carry Out Your InvestigationYou will now use the simulation to investigate how the motion of an object is affected by its mass. Based on the results from your investigation, you should be able to estimate the mass of the mystery object .Plan out how you will carry out this investigation. Write the steps to your plan on the next page. Also create a data table to help keep your data organized as you carry out your investigation. Get your teacher’s approval before carrying out your investigation. Teacher Approval ______Steps: Data Table:Mass and Motion QuestionsUse your data to describe how the motion of an object is affected by its mass.Why do you think this happens? Explain.What variables did you keep constant in this investigation? Why?Was there a sum of forces acting on the objects you used in your investigation? Explain your answer.How much do you think the mystery object weighs based on your data? Explain the reasoning behind your answer.Investigate: Part II- Forces (including friction) and MotionMaterialsFriction SimulationOnline Stop watch Simulation PracticeClick the “Friction” thumbnail on the bottom.Check all the boxes in the right hand corner (forces, sum of forces, values, masses and speed).Remove the wooden crate from the ground and replace it with the refrigerator. Use the black arrows at the bottom to change the “Applied Force” to 500 N. The screen should look like this: What happened? Did the refrigerator move?Click the “Reset” button.Recheck all the boxes in the upper right hand corner.Replace the box with the refrigerator and set the “Applied Force” to 500 N again. Slide the friction tab toward “None”.What happens as you slide the fiction tab closer to “None”? Observe the speedometer, individual forces and sum of forces.Continue playing with the simulation until you feel comfortable understanding how to change objects, how to change the “Applied Force” and “Friction”, what the force/values/masses and speed show you, etc. Once you feel comfortable with this, you are ready to plan your own investigation!Plan and Carry Out Your InvestigationYou will now use the simulation to investigate how the motion of an object is affected by the sum of forces acting on it. Plan out how you will carry out this investigation. Write the steps to your plan below. Also create a data table below to help keep your data organized as you carry out your investigation. Get your teacher’s approval before carrying out your investigation. Teacher Approval ______Steps:Data Table:Forces and Motion QuestionsUse your data to describe how the motion of an object is affected by the forces acting on it.What variables did you keep constant in this investigation? Why?How was the sum of forces acting on the objects related to the individual forces acting on the object? Justify your answer. What happens if there is too much friction? Will the object move slowly, fast or not at all? What if only a little friction is added, how will the object move?Based on your investigation using the simulation, complete the following table. ObjectApplied Force (N)Friction Force (N)Sum of Forces (N)Crate200125Man472272Refrigerator5199Girl363100Garbage Can 500375 You can use the simulation tab to check you answersTry calculating the Sum of Forces on the previous table using the number sentence or equation you came up with in #13 on the second page, but now using Ffriction and Fapplied. Do you get the same answers as from the simulation? If you did not, how can you revise your number sentence or equation to match the Sum of Forces provided in the simulation?Let’s call all applied forces positive and all friction forces negative. Use the equation from #17 to complete the table. SummaryObjectApplied Force (N)Friction Force (N)Sum of Forces (N)Box-210190Man350274Refrigerator-137363Girl200122Garbage Can -50100Mystery Object300175A shopping cart full of groceries accelerates at 2 m/s2. Describe two different ways that the acceleration of the shopping can be doubled. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download