1. Wednesday(09/23): Introduction to Forces (Ch.5) and Newton's Laws

of Motion. The Fundamental Forces. HW: Read Ch.5, pages 112-22 and solve

prob. 3, 7, 9, 11, 15, and 17 on pages 140-1.

2. Thursday(09/24):  Applications of Newton's Laws. The Force of Friction.

HW: Read pages 122-138 and solve prob. 21, 23, 25, 29, and 33 on

pages 142-3.

3. Friday(09/25): Lab experiment on the Atwood Machine. HW: Process all

Lab data and solve problems 37, 39, 41, and 43 on page 144.

4. Monday(09/28): No School - Fall Holiday. HW: Continue to work on all

assignments.

Homecoming Week. Dress Up!

5. Tuesday(09/29): (Dress Sailor) Post-Lab discussion. HW: Complete

lab report and write Abstract (due Thursday).

6. Wednesday(09/30): (Dress Beachware) Review I Ch.5.

HW: Complete Review handout.

7. Thursday(10/01): (Jammin' in Jamaica - Class Colors) Review II

Ch.5. HW: Complete Review handout.

8. Friday(10/02): (Bermuda Triangle Blackout) TEST on Ch.5 - Forces

and The Laws of Motion (Finish Test on Monday). HW: Go to web-site for

notes on Ch.6 - Circular Motion and Other Applications of Newton's Laws.

1. A force is a push or a pull on an object. A force can act through physical

contact (contact forces) or at a distance (field forces).

2. All forces are vectors because they have both magnitude and direction.

A free-body diagram shows force vectors as arrows.

3. The unit of force in MKS is the Newton, named after Isaac Newton who

lived from 1642 to 1727.

4. A Newton is another name for a kg m/s². In CGS we use the Dyne as a

unit of force.

5. The four fundamental forces are gravitational, electromagnetic, strong

nuclear, and weak nuclear.

6. Isaac Newton determined that the causes of motion are forces. This study

is known as Dynamics. Recall that Galileo (1564-1642) developed Kinematics.

7. We still have the five motion formulas from the study of kinematics. We

know them as: (a) Δx = v_avg·Δt , (b) v_avg = (v_i+v_f)/2 , (c) v_f = v_i + a·Δt ,

(d) v_f² = v_i² + 2a·Δx , (e) Δx = v_i ·Δt + ½a·Δt² .

8. Newton summarized all motion with his three laws. Law I: An object will

remain at rest or in a state of constant motion if the forces acting on it are

balanced. This is known as the Law of Inertia.

9. Law II: The acceleration of an object is directly proportional to and in the

direction of the net force, but varies inversely with the mass. From this law

we get the equation that F_NET = ma .

10. The net force is the vector sum of all forces acting on an object.

11. Law III: For every action force there is always an equal and opposite

reaction force.

12. We can now state the difference between mass and weight. Mass is the

measure of the amount of matter in an object. Weight is the force of gravity

on the object.

13. The MKS unit of mass is the kilogram (kg), while the unit of weight is the

Newton (N). In CGS we use grams (g) and Dynes (Dyn).

14. To change mass to weight, use the equation F_g = mg . This is the same

as F = ma , with g = 9.8 m/s².

15. There are two kinds of mass, gravitational and inertial mass. They are

numerically equal but are determined in two different ways.

16. Friction is a force that opposes the motion of an object. It is a type of

electromagnetic force and is caused by surface conditions and the weight of

 the object being moved.

17. The force of friction is determined by multiplying the coefficient of friction

and the normal force, F_f = μF_N . The normal force is the contact force of one

surface on another. Normal means perpendicular.

18. The coefficient of friction is given by the Greek letter mu, μ .

19. Static friction is greater than kinetic friction.

20. And still, we need these steps to solve any problem in Physics:

(i) read the problem and identify the given variables

(ii) determine what you are asked to solve for

(iii) find the correct vector formula to use

(iv) use Algebra, Trigonometry, and/or Calculus to isolate the unknown

(v) substitute-in the given information and simplify.