## Overview

The material on this page will provide you with everything you need in order to be successful with the forces unit.  It cannot be stressed enough how important it is to read the assignments posted here.  Even if you are in class everyday, it will still be hard to grasp all of the material associated with forces.  Forces is a key concept in physics and it is therefore necessary to understand all of the concepts very thoroughly in this unit.  This unit provides you with information that will be necessary to retain throughout all other units in physics.  In other words, it is really, really, really, really, really important that you fully understand the concepts in this unit - really important!

## Objectives

By the end of the forces unit, you should be able to:

1. Explain what is meant by the term inertia.
2. Be able to describe the difference between mass and weight.
3. Define Newton’s second law of motion and be able to explain how a force can cause an object to accelerate.
4. Calculate the the force, mass or acceleration associated with an object given two variables.
5. Compare and contrast scalar and vector quantities. Give at least three examples of each.
6. Explain how various action-reaction force pairs support Newton's 3rd Law of motion.
7. Be able to design a free body diagram labeling all relevant forces present based on a given scenario.
8. Be able to determine the direction of an object's travel based on a given free body diagram.
9. Calulate the net force or acceleration an object will experience based on a given free body diagram.

## Agenda

Main goal:

Be able to calculate net forces based on various forces acting upon given objects. (2.3, 2.5)

Class Agenda:

1. Review 1D Motion Exam
2. Briefly overview Newton's 3 Laws of motion (pg. 1)
3. Begin calculating net force (pgs. 10-13)

Homework:

1. Complete pages 10-13 (scroll to bottom for videos and answer key)

Main goal:

Be able to describe the motion of objects based on inertia and acceleration. (2.1 - 2.3)

Class Agenda:

1. Review net force calculations (pgs. 10-13)
2. Discuss the concept of inertia
3. Bridge research project
4. Discuss the concepts of mass vs. weight (pg. 2)

Homework:

1. Attempt page 14 in Force packet (scroll to bottom for videos and answer key)

Main goal:

Be able to sketch free body diagrams for given scenarios. (2.6-2.9)

Class Agenda:

1. Discuss Free Body Diagrams (FBD)
2. Complete FBD practice (page 14)
3. Finish planning balsa wood bridge design
4. Begin building balsa wood bridges

Homework:

1. Complete page 14 in forces packet (scroll to bottom for videos and answer key)

Main goal:

Be able to solve for force, mass, and acceleration using the force formula. (2.4)

Class Agenda:

1. Discuss Newton's 2nd Law in greater depth
2. Practice calculating force, mass, and acceleration using Newton's Law of Acceleration (pg. 5)
3. Continue balsa wood bridge construction

Homework:

1. Complete practice calculations on pages 5-6 (scroll to bottom for videos and answer key)

Main goal:

Be able to sketch free body diagrams for given scenarios. (2.6-2.9)

Class Agenda:

1. Review Newton's 3 Laws
2. Review free body diagrams
3. Practice using free body diagrams (pages 15-16)
4. Continue balsa wood bridge construction

Homework:

1. Complete pages 15-16 in forces packet (scroll to bottom for videos and answer key)

Main goal:

Be able to sketch free body diagrams for given scenarios. (2.6-2.9)

Class Agenda:

1. Review force calculations (pgs. 5-7)
2. Use free body diagrams to determine how terminal velocity works (pgs. 8-9)
3. Continue balsa wood bridge construction

Homework:

1. Complete pages 8-9 in Forces packet (scroll to bottom for videos and answer key)

Main goal:

Review all material from the forces unit. (2.1-2.9)

Class Agenda:

1. Solve for net force and acceleration upon sketching free body diagrams with multiple forces present (pg. 17)
2. Review free body diagrams and net force (pg. 18-19)
3. Continue constructing balsa wood bridges (last day!)

Homework:

1. Begin studying for test on 10/22 or 10/23
2. Catch up on any work in forces packet (pages 1-2, 5-19 should be complete by next class)

Main goal:

Apply Newton's Laws of Motion to determine the most effective bridge designs

Class Agenda:

1. Begin balsa wood bridge reflection assignment (this is the assignment where your grade for the project comes from!)
2. Balsa wood bridge testing competition

Homework:

1. Complete balsa wood bridge reflection

Main goal:

Review all material from the forces unit. (2.1-2.9)

Class Agenda:

1. Be able to describe the relationship between Newton's 3 Laws and various force demonstrations.
2. Review effective bridge design using force components to determine where forces are present as downward forces increase
3. Complete review exercises for exam next class (pgs. 20-23)

Homework:

1. Complete forces packet, review notes, watch videos as needed, check answer keys, etc. in order to review for exam next class!
2. Pages 1-2, 5-23 of Forces packet should be complete. Pages 20-21 will be checked for credit.

Main goal:

Show all of the knowledge that you have gained during this unit (2.1-2.9)

Class Agenda:

1. Brief Review
2. Exam
3. Review previous units

Homework:

1. Complete Objective 0/Objective 1 Check (due next class)

All of the readings for this unit will be from the physicsclasroom.com website.  This is a phenomenal website that makes difficult concepts much easier to comprehend.  For the forces unit, we will be using the "Newton's Laws" section of the website.  It is highly recommended that you familiarize yourself with this additional resource.  The following readings are most applicable to our forces unit:

## Forces Unit Answer Key

Forces Packet Answer Key

It is VERY importatnt that you try the problems in the forces packet without looking at the answer key while doing the work. This can give you a false sense that you are understanding the concepts while you may not be truly understanding them.  Use the answer key at your discretion - meaning use it wisely!  Do the practice problems on your own and then look at the answers after you have completed them.  If you are not understanding a concept, it may be useful to work one problem in reverse and then put the answer key away while working others using that problem as an example.

## Video Explanations

Still not comfortable with the material?  Try following along as nearly all problems in the packet are solved in the following video tutorials here.

Contact: Jeff.Batey@D214.org