1. Science Starter
Take out your yellow sheet and complete next 2 problems
Take the first 5 minutes and try to complete them on your own!!
Place on your desk: Modeling Energy (both HWs), Conservation of Energy Lab

2. DEADLINE FOR SUBMITTING PAPER WORK EXTENDED TO TODAY 4pm
AP EXAM SIGN UP
DEADLINE FOR SUBMITTING PAPER WORK EXTENDED TO TODAY 4pm

3. Today’s Agenda Science Starter- Warm Up Review Packet Final
Energy & Work
Energy & Non-conservative Forces Lab
Davidson NEXT
Unit 4 Summary

4. Lesson Essential Question
What does it mean for energy to be conserved?

5. Kf+(Ug)f+(Us)f+ΔEth = Ki+(Ug)i+(Us)i
Energy & Work
Kinetic Energy is energy of motion
K=1/2(m)v2
Gravitational Potential Energy
Ug=mgh
Elastic Potential Energy
Us=1/2(k)x2
Thermal Energy (friction)
ΔEth = fkΔx
If a system is isolated and friction is present then…
Kf+(Ug)f+(Us)f+ΔEth = Ki+(Ug)i+(Us)i
Basic Energy Model
Work: transfer of energy by mechanical forces (W=Fdcosθ)
When work is done on a system, the system’s total energy changes by the amount of work done
ΔE=ΔK+Δug+…=W
If a system is isolated, W=0

6. Energy & Non-Conservative Forces Lab
Problem: Determine the amount of energy dissipated by friction in a system consisting of a modified Atwood machine (.5 meters)
Materials: Wood block, wood board, frictionless pulley, string, meter stick, mass, mass hanger
What information are you given?
Coefficient of friction: u=0.4
Mass of block: 0.7 kg
Lab must include: procedures, system, bar charts, mathematical representations, data table and analysis, conclusion, and explanation of any errors

7. Modified Atwood Machine (50 minutes)

8. Davidson NEXT
Take a computer and go to the following website: edge.edx.org
Login using your username you created and a password
You should see a course for Physics 1
When you open the course go to Rotational Motion
Read Overview & Objectives, continue on through the module in order
Can do alone or in partners!

9. Summary & Homework Complete the conservation of energy problems
Watch intro to momentum video (Khan Academy)
Complete Lab Report (same rubric as last lab)

10. Wfriction=ΔE= fkΔx=ukmgΔx=(0.4)(0.7 kg)(9.8m/s2)(0.5m)=1.372 J
Checking Our Work
Experimental Values:
What you find in the lab
Should have found velocity, height, distance moved, and masses of moving pieces
Actual Values:
What the numbers should be
Check your work with the following equation
Wfriction=ΔE= fkΔx=ukmgΔx=(0.4)(0.7 kg)(9.8m/s2)(0.5m)=1.372 J
Calculating Percent Error