AP Physics 1
Energy Labs
Do each of the following labs/activities in your lab notebook. What is required for each write-up is included in the
directions.
POP-UPs:
Introduction:
Play with the Pop-Up. Think about the energy transfers involved in a Pop-Up spring toy. In words and pictures describe
the energy transformations that are occurring.
Investigate:
We want to find the spring constant (k) of the popper. We also want to find the initial velocity of the popper once the
spring has “sprung”.
Once you have a plan, write the procedures in you notebook and then execute your plan. Neatly (please!) show your data
and calculations. Make sure you answer both questions.
Conclusion:
Now consider what would be different if additional mass was added onto the popper. What variables (that you measured
or calculated) would change? Would they increase or decrease? WHY? How about the energy at each step, would they
change? Answer in a full paragraph (several well-reasoned sentences). Pictures and equations may help, but you need
to explain in words as well!
Now one step further:
Lets try to confirm your answer for the Pop-Up’s initial velocity as it leaves the ground. Take a video of the Pop-Up
popping with your phone. Be sure to include a ruler/meter stick in video. At home use Logger Pro video analysis to find
the initial velocity. (Since you have used Logger Pro only once, you may want to revisit the directions on the Haiku page.
I have re-posted in our current unit the directions from the basketball shot video analysis lab.) Compare your two answers
for the initial velocity (percent difference). Include a screen print from Logger Pro with the velocity/time graph showing.
Ramp/Marble/Projectile Motion:
Introduction:
Here you are going to re-do a lab from earlier this year, but look at it from a different point of view. You rolled a marble
down the ramp, used a photogate to find the velocity the marble would be launched with, and predicted the landing
location. This time you will not use a photogate. You will find the velocity using energy principles.
Collect Data:
Before getting a marble, gather what data you need to find the launch velocity. With you lab partner(s), calculate the
launch velocity and a predicted landing spot. Show all of these measurements you made in a well labelled diagram and
neatly/clearly show all calculations. (Yes I have to read this!)
Launch:
Obtain a marble and a “half-cup” target and let it fly!
Analysis:
Calculate your percent error for your prediction for the landing spot. Where do you think the error is coming from?
Pendulum:
We want to see if energy is conserved in a pendulum. Make sure the center of the “bob” goes through the photogate
timer at the correct location by adjusting the string at the top of the pendulum. The length of the pendulum is from the
bottom of the peg to the bottom of the washers. Hold the bob at 30˚ and gently release. Catch the bob so it won’t pass
through the timer again. To calculate the energies, you will also need the mass of the “bob” + washers.
Calculate the energy at the start of the swing and calculate the energy at the bottom of the swing. How close (percent
difference) are they? For your calculations at the top of the swing, you will need a well labelled diagram and have to do
some trig along the way. For the bottom of the swing, use a photogate to find the velocity. (Remember how to find velocity
using a photogate!)