• http://dhs.dist113.org/faculty/piggottk/website/FrPhysics/FR_PHYSICS/UNIT%202-Newtons_Laws/LAB-Mousetrap_Cars.doc

    Freshman Physics              Name:________________________________ Per:____

    LAB: MOUSE TRAP CARS                                  Due Date:_____________________


    C:\Documents and Settings\piggottk\Local Settings\Temporary Internet Files\Content.IE5\82M39JWU\an04317_[1].wmfINTRO:  In this unit we will be learning about Newton and his laws of motion.  Each law of motion, while distinct, involves forces and its subsequent effect on motion.  In this lab, we will be constructing a “car” that is powered simply by the force exerted by the mousetrap spring.  Mousetraps usually store one joule of energy (which is lethal to a mouse). 

    Everyone will start with the same mouse traps (Victor brand) and will only be allowed the use of one trap for their car’s construction.  This is a very INQUIRY based experiment (i.e.-you will have to think and research for this one!!)  GOOD LUCK!


    PURPOSE:  How will we build cars that are powered from the stored energy in a mousetrap’s spring that can travel long distances (at least 5m) in a short amount of time and/or be creative in design?



    1.      Brainstorming (get approval before moving on to the next question)

    Parts of Car

    Possible Materials

    Affect on Motion










    Lever Arm










    Teacher’s OK:______________

    2.      Detailed sketch of proposed design (get initials before moving forward):

    It is important to have an idea of what your car will look like and how it will operate BEFORE you start building it.  You may have to modify the design slightly as you work out the “quirks”, but you have to have a starting point.



















                                                                                                    Teacher’s OK:____________

    3.      Shopping list:

    Your shopping list does not need to be long, nor does it need to cost a lot to build a great mousetrap car!  You can probably find most items at home in an old toy bin.  What you can’t find, you should be able to purchase from most home hardware stores inexpensively.

    Lab Partner

    Needed Material

    Store to Buy From/Bring from Home

    Approximate Cost

    Ms. Piggott


    Provided by Ms. P!

    $0.00 J

















    NOTE: You may not buy/use a mousetrap car kit!!!  Cars designed from prepackaged kits will be disqualified from the lab


                                                                            MATERIALS ARE DUE BY:______________


                                                                                        Teacher’s OK:_____________



    Table 1: Calculating Speed of Mousetrap Car

    Trial #

    Distance (m)

    Time (s)

    Speed (m/s)


















    Table 2: Possible Bonus Points (Bonus CANNOT exceed 15 points per group)


    Longest Distance (m)

    Fastest Speed (m/s)

    Most Creative

    Grand Total

    Extra Credit Possible







    Docfizzix: (Remember don’t buy the kits!!)


                   If you are having specific trouble with your car, Doc Fizzix can help you fix it!


    The Best in Mousetrap Cars


    A link to Lots of Other Mousetrap Car Links!


    Mousetrap Cars


    Mousetrap Cars Planner – includes pictures


    Construction Tips


    (there is an underscore between “construction” and “tips”)

    PBS Mousetrap Car




    1.      Describe why Newton’s First law is also called the Law of Inertia.





    2.      What property of matter is related to inertia?  How could this information be applied to the selection of materials for your mousetrap car?  Explain.





    3.      Draw a force diagram for your car before you let it go.












    4.      What type of motion is the car in at this phase?  As a result, what would the net force be?  Explain how you know this.




    5.      Draw a force diagram for your car right after you let it go (when the string is still pulling the back axle).












    6.      What type of motion is the car in at this phase?  As a result, what would the net force be?  Explain how you know this.





    7.      Would having a longer string and lever arm be beneficial or harmful to the motion of your car?  Why?  (HINT: What force(s) would be present while the string is pulling??)








    8.      Draw a force diagram for your car after the string has been pulled all the way around the axle (i.e.-the string has become detached).












    9.      What type of motion is the car in at this phase?  As a result, what would the net force be?  Explain how you know this.






    10. How do the forces on the mousetrap car compare while the car is speeding up to when the car was first released?

    o A. The forward force on the car is greater than friction.

    o B. The downward force on the car is balanced by the forward force.

    o C. The force from the mousetrap is balanced by the friction on the car.

    o D. The force of gravity is greater than the force up from the floor on the car.


    11. Summarize your findings of this lab in relation to Newton’s 1st law.  Do you think this lab helped reinforce the concept of Newton’s 1st law or no?  Why?









    NEWTON’S 2nd LAW


    1.      What is the definition of acceleration?




    2.      How does Newton’s 2nd law relate the acceleration, mass, and force of an object?  Write the equation below.




    3.      Using a spring scale, determine the amount of force, in newtons, the spring is providing for the car at each level of incline for the lever arm.


    Angle (degrees)

    Force (N)

    How to Measure Force with a Spring Scale



















    4.      What is the mass of your car in grams?   Convert this number to kilograms.






    5.      Calculate the average acceleration of your car using the equation:


    a = ---------



    **NOTE: Use the average force (N) from #3


    6.      What force(s) caused the mousetrap car to eventually come to a stop?







    NEWTON’S 3rd LAW


    1.      State Newton’s 3rd law below.





    2.      What was the action force that was being applied to the back axle of your mousetrap cars?





    3.      What was the subsequent reaction force?





    4.      What do you know about the reaction force compared to the action force?








    5.      Do the action and reaction forces act upon the same object?  How do you know?





    6.      Draw a force diagram of these action-reaction forces below.









    7.      Explain what would happen to the motion of your mousetrap car if you had wound the string around the back axle of the car forwards instead of backwards.  Make sure you use Newton’s 3rd law to quantify and qualify your response.