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 theconcrete sidewalk?

•What would you need to know to answer this question?

•What other forces could influence the outcome?

Investigating Falling Objects

Drop the ball onto the motion detector from 4 different heights.

What is the “change” that is being measured?

Purpose: How does an object’s drop height (and its GPE) affect its speed as it falls?

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?

WORK UNIT:______ GPE UNIT:______ FORCE UNIT_____

Complete in your Journal: Left Side

Answer the following word problems Question #1: A 2.8 kg text Question #2: a 84 kg

student is book is on a table that is standing on top of bleacher that3 meters high are 12 meters high

Mass = Mass =

Gravity = Gravity =

Height =_________ Height =___________

GPE = 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

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

Air Resistance Lab

GPE Lab Report- Due Tuesday Introduction-

Hypothesis: 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 LAB- explain what the data says

Conclusion- How does height and air resistance affect speed as something falls? What did you learn? Tell me about GPE