Monday (Sep 27):

Key Concept(s) Today: Inertia & Friction

Journal: (1st Law - Inertia)

Using Inertia, provide a short explanations for each of the following.

1. A biker flies over the handlebar if he hits the brakes too hard on a dry road. Why?

2. Headrests are placed in cars to prevent whiplash injuries during rear-end collisions. Why?

3. A car goes straight off the road when it hits ice on a sharp bend. Why?

 L#7:  1-3, 7 - 14, 17   Due Today Mon 27 Sep (Motion & Avg Acceleration)

Tues 28 Sep Lab: Rolling Gyro's

 L #8: 1- 7, 12, 15, 18    Due Wed 29 Sep  (Friction)

Thurs/Fri    30Sep/1 Oct Library ( Key scientists)

Monday 4 Oct Lab: Graphing Motion

Power Point (Key Scientists) due Tuesday 5 Oct

L #10: 1- 3, 7 - 10, 14, 17    Due Wed 6 Oct (Motion Graphs)

Thursday 7 Oct  Lab: Ball Toss

L #11:  1- 4, 9, 11,  13, 15, 18 Due Mon 11 Oct (Newton's 2nd & 3rd)

Tues 12 Oct Lab: Unknown Mass

L #14:  1- 3, 5, 10, 11, 14 Due  Wed 13 Oct  (Free Body)  

Thurs 14 Oct:

Re-View for Test tomorrow on Newton's Laws

Fri 15 Oct: Test Newton's Laws

L #9: 1- 8,  11-16    Due Mon 18 Oct (Torque)

L #12: 1- 14,  16, 17    Due Wed 20 Oct (Work & Power)

L #13: 1- 13,  18, 19    Due Friday 22 Oct (Instantaneous Vel & Acc)

Notes:

Newton's 1 law

Riding in a Car

The common experience of riding in a car provides some excellent examples of Newton's First Law in action.

Situation:

Your car is at rest. Suddenly you push down on the "accelerator" and the car accelerates forward. You feel that you are pushed back into your seat.

Common Explanation:

"G Forces," caused by the acceleration, push you back into your seat.

Is this Correct or Incorrect Explanation - explain

Explanation:

First of all, there is nothing pushing you back in your seat! (Acceleration is a concept, not an object, and only objects can push you.  You were at rest, so you remain at rest. The car accelerates forward, and you stay where you are. Force of seat is pushing you forward.

Situation:

You are moving at constant velocity (constant speed in a straight line). Suddenly you apply the brakes. You feel "thrown forward" into the dashboard!

Common Explanation:

You are thrown forward.

Is this Correct or Incorrect Explanation - explain

Problems with the Common Explanation:

What throws you?

Correct Explanation:

You are moving with a constant velocity. You keep that velocity (while the car slows down) until something stops you.

Turning - "Centrifugal Force"

Situation:

You go around a curve (at constant speed). You feel pulled toward the outside of the curve.

Common Explanation:

The "centrifugal force" pulls you to the outside of the curve.

Is this Correct or Incorrect Explanation - explain

Problems with the Common Explanation:

What exerts this "centrifugal force"?

Correct Explanation:

You were moving with a constant velocity (straight line at constant speed). The car turned, and you didn't (since Newton's First Law says your velocity stays the same unless an unbalanced force acts on you.)

Questions:

1.   Does speed have a direction?

2.   Does velocity have a direction?

3.   What three things can one do to change velocity?

4.   Does force have a direction?

5.   Does acceleration have a direction?

6.   If acceleration is “0” is it moving?

7.   If velocity is “0” is it moving?

8.   If velocity is “0” can it be accelerating?