Forces Review Answer Key

Unit Three: Newton's Laws of Motion

Goals

1.      Draw Force Vectors.

2.      Calculate Weight.

3.      Solve Problems with Net Force.

4.      Know that when an object is at rest or moving with constant velocity that F_net = 0 and all of the forces are balanced.

5.      Understand what terminal velocity is and how it is reached.

6.      Be able to explain why all objects in freefall have an acceleration of 9.8 m/s²

7.      Understand that forces are interactions between two things and that each object exerts an equal and opposite force on the other.

8.      Know Newton’s Three Laws of Motion by name.

In general, understand Newton’s 3 laws and apply them to explain motion.

Lab Due Date:  Nov. 1 

Homework due in the evening of Nov. 6

Test Date and Beverly Cleary Presentations:  Nov. 13 and 15  TBD

PreUnit Reading

Unit Three - Newton's Laws of Motion

Please either preview chapter 6 in the textbook or read Lessons 1 and 2  (each has 4 parts) at the following link.http://www.physicsclassroom.com/Class/newtlaws/

Then do the the 6 questions in the new UT homework assignment.  Due Monday night at 10:00.

Key concepts here are  inertia, force, mass vs. weight, and net force.

Practice Sheet for Vector Unit

Answers are on the last page.Motion in 2 Dimensions Practice

Unit Two - Motion in 2 Dimensions

Unit Goals:

1. Know that perpendicular vectors are independent

2. Add vectors graphically with parallelogram and head to tail methods.

3. Use trig and Pythagorean theorem to find resultant.

4. Break vectors into perpendicular components graphically and with trig.

5. Solve motion problems in 2D.

Test – Thursday,  Oct, 18

Homework due

10:00 pm Wednesday  the 10^th (9 Questions)

10:00 pm Wednesday  the 17^th (17 Questions)

Vectors preview

Prior to going over this in class, try reading these three pages from the physics tutorial website or reading  chapter 4 from the textbook and answering the three on line homework questions on Quest (due Wed. night)

http://www.physicsclassroom.com/Class/vectors/U3L1a.cfm
http://www.physicsclassroom.com/Class/vectors/U3L1b.cfm
http://www.physicsclassroom.com/Class/vectors/U3L1c.cfm

Kinematics Review Sheet

I've identified several mistakes on the key. P 2 problem 5 The graph should be a straight line sloping up from the origin. I had made the position graph not the velocity graph.
 p2. problem 8 part b The displacement should be 20m. I had accidentally used 20m/s instead of 30m/s.
 p.4. The units for part b should be m/s^2

Kinematics Review 2012