Warm-up


How much force would be needed to move a dog
that is 65kg at an acceleration of 2 m/s2? (Find the
weight!)
Find the Weight for the following:
m
= 25kg
 m = 101 kg
 m = 12.5 kg
 m = 850 kg
Can a penny dropped from the
top of the Empire State Building
have enough energy to crack the
concrete sidewalk?
•What would you need
to know to answer this
question?
•What other forces
could influence the
outcome?
Investigating Falling Objects
Purpose: How does an object’s drop height (and its GPE) affect its speed as it
falls?
Drop the ball onto the motion
detector from 4 different
heights.
What is the “change” that is
being measured?
What patterns did you observe in the data?
GPE = mass x gravity x height = mgh


So can the penny crack concrete if it is dropped
from the top of the Empire State Building?
As the GPE transforms into KE, the speed at
which the penny strikes the sidewalk should be
about 200 miles per hour!
Mythbusters “Death By Falling Penny

http://www.youtube.com/watch?v=QUS89-_fbtk
A discrepancy in the data?



When tested, the falling speed of the penny was
only about 65 miles per hour.
What happened?
Where did the energy go?
Complete in your Journal: Left Side
WORK UNIT:______ GPE UNIT:______ FORCE UNIT_____
Answer the following word problems
Question #1: A 2.8 kg text
book is on a table that is
3 meters high
Mass =
Gravity =
Height =_________
GPE =
Question #2: a 84 kg student is
standing on top of bleacher that
are 12 meters high
Mass =
Gravity =
Height =___________
GPE =
Air Resistance Lab

Did Air resistance play a role in yesterdays lab?
 Let’s

Find out!
You will be working in same groups as yesterday
 Assign
Roles!
 Recorder
 Dropper
 Measurer
 Manager
Air Resistance Lab



Mass of 1 Coffee Filter is 1.6 g as you add a
coffee filter times by the number you have
Calculating Terminal Velocity- 1 divided by the
speed you calculated
Averages: add the 7 trials together and divide by 7
GPE Lab Report- Due Tuesday

IntroductionHypothesis: If the distance doubles then the speed should
double as well
 Purpose: To determine what affects an object’s GPE
 Explain the purpose as well- give some details





Procedure- tell me what we did in BOTH labs
Data- Give me data from BOTH labs (the ball lab you
should have your data in your questions that you
answered)
Analysis- Give me two graphs one from Each LABexplain what the data says
Conclusion- How does height and air resistance affect
speed as something falls? What did you learn? Tell me
about GPE