Name:                                                  Period:

     Energy is the measure of how much work an object can do.  Any object that is capable of doing work must have energy of some sort. An object gives up its energy when it does work, but the result of that work is to give it a different type of energy or to give another object energy, either kinetic or potential.  The net effect when an object does work is that the energy is transformed from one kind to another or is transferred from one object to another.  Whenever energy is transformed, the total amount of energy present does not change.  In this lab we will investigate the relationship between work, kinetic energy and potential energy in a simple pop-up toy.

                                                                                                                        W = E gained/lost

                        GPE = mgh                             KE = ½ ms2                          W = Fd

     h =                                 s =               F =

                    where g = 9.8 m/s/s                                                                d =

1.  Set the eyeball popper, place it on the table and let it go.  Observe what happens and explain how energy is transformed in a pop.  (Draw a diagram of the poppers motion and label the types of energy and their transformations.)

 

 

 

 

 

 

 

 

2. Measure the Mass. Use a triple beam balance to measure your eyeball popper’s mass, then convert it to kilograms by dividing by 1000.

                                                                                                Mass =                         g =                       kg

3.  Measure the height that the popper reaches at the top of its flight.  Do this for five trials and average your results.

Height:

            trial 1 _________

            trial 2 _________

            trial 3 _________

            trial 4 _________

            trial 5 _________

 

 Average Height:                                  meters

 

 

 

4.  Calculate the Gravitational Potential Energy (GPE) that the eyeball popper has at the top of its flight.  Show your work. 

 

 

                                                                                    Gravitational Potential Energy = ____________J

 

 

5.  Based on the Law of Conservation of Energy, how much kinetic energy did the toy have when it left the table and began its flight?  Explain how do you know this answer without having to use an equation.

 

 

 

 

 

 

 

                                                                                                Kinetic Energy at Start of Flight =                    

 

6.  How much kinetic energy will the toy have after it has fallen from the top of its flight and is just about to hit the table top?  Explain how you know this answer without having to use an equation.

 

 

 

 

 

 

                                                                                                Kinetic Energy at End of Flight =                    

 

7.  How much elastic potential energy did the toy have when it was sitting on the table about to pop?

Explain how you can know this answer when you don’t even have an equation for elastic potential energy:

 

 

 

 

 

                                                                                    Elastic Potential Energy =                     

 

 

 

8. a)  At what moment in its flight does the toy’s elastic PE become KE?

 

 

 

 

 

b) How much Work did the toy do using its elastic potential energy in order to launch itself off the table? 

 

 

                                                                                                      Work =                

 

c) By using a small ruler figure out the distance the popper has to move to launch itself off the table. (How far did it move while it was still touching the table?)

 

                                                                                                                                Distance =                   

 

    d)  Solve for the Force applied by the toy as it pushed off the table, using the equation for WORK.

       

                                                                                     Average Force =     

 

9.  How fast is the popper going just after it leaves the table?  Hint: look back to question 5 and your equations involving KE.

 

 

 

 

                                                                                     Speed = ________________

 

10.  How fast is the popper going just before the end of its flight? Hint: look back to question 6 and your equations involving KE.

 

 

 

 

                                                                                     Speed = _______________

 

 

11.  What happens to all of the energy that the eyeball popper had when it lands on the table and comes to a stop?

 

 

 

 

 

 

CHALLENGE:

12.  If it landed on the floor instead of on the table, how fast would it be going?  (Hint:  how far does it fall to the floor, what is its GPE from the top of its path to the floor?  What does that mean about energy?)