1. Tuesday(09/22): Introduction to Forces (Ch.4) and Newton's Laws.

HW: Read pages 81-93. Solve prob. 3, 7, 13, and 19 on pages 116-117.

2. Wednesday(09/23): Force of Friction and the Inclined Plane. The

Tension Force and Equilibrium. HW: Read pages 93-112. Solve prob. 35,

37, 39, 47, and 51 on page 118.

3. Thursday(09/24): Chap. 5 - Circular Motion and Centripetal Force.

HW: Read pages 125-133. Solve prob. 5, 7, and 11 on page 143.

4. Friday(09/25): Banked Curves and other applications.

HW: Re-read pages 133-141. Solve prob. 21, 29, 33, and 37 on

pages 144-5.

5. Monday(09/28): No School Due to Fall Holiday. HW: Finish all

assigned homework.

Homecoming Week. Dress Up!

6. Tuesday(09/29): (Dress Sailor) Lab Experiment on Resolution of

Forces. HW: Process lab data and write Lab Report, due Friday.

7. Wednesday(09/30): (Dress Beachware) The Tension Force and

Circular Motion. HW: Read pages 133-141. Continue to solve prob. 21,

29, 33, and 37 on pages 144-5.

8. Thursday(10/01): (Jammin' in Jamaica - Class Colors) Applications

of Newton's Laws and . HW: Solve prob. 5, 23, and 27 on pages 116-117

and 14 on page 143.

9. Friday(10/02): (Bermuda Triangle Blackout) Review I Ch.4 & 5 -

Newton's Laws and Applications. HW: Finish all handouts.

10. Monday(10/05): Review II Ch.4 & 5 - Newton's Laws and

Applications. HW: Finish all handouts.

11. Tuesday(10/06): TEST on Ch.4 & 5 - Newton's Laws and the

Applications of the Laws. HW: Go to web-site for notes on Ch.6&7-

Work, Power, Energy, Impulse, and Momentum.

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 Gravity, Electromagnetic, Strong

Nuclear, and Weak Nuclear. We can calculate the Gravitational Force

between two masses using  F_G = G·m₁m₂/r²  with G = 6.67x10^-11 Nm²/kg².

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

developed by Galileo (1564-1642). We know them as:  Δx = v_avg·Δt ,

 v_avg = (v₀+v)/2 ,    v = v₀ + a·Δt ,    v² = v₀² + 2a·Δx ,

  Δx = v₀ ·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. (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 . (Law of Acceleration)

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

reaction force. (Action-Reaction)

11. 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.

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

Newton (N).

13. To change mass to weight, use the equation F_G = mg . This is the same

as F = ma , with g = 9.8 m/s².

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

numerically equal but are determined in two different ways.

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

electromagnetic in nature.

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

and the normal force, F_f = μF_N .

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

Normal means perpendicular.

18. The normal force is the contact force of one surface on another.

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

20. Static friction is greater than (sometimes equal to) kinetic friction.

Ch.5 - Dynamics of Uniform Circular Motion.

1. Newton's second law applied to a particle moving in uniform circular

motion states that the net force must be toward the center.

2. Uniform circular motion occurs when an acceleration of constant

magnitude is perpendicular to the tangential velocity and the object

maintains a constant speed but is accelerated toward the center of

the circle.

3. This introduces the concept of centripetal acceleration, a_C = v²/r ,

and, by Newton's second law, centripetal force, F_C = mv²/r .

4. The central force acting on an object that provides the centripetal

acceleration could be have its origin in the following: (i) the force of

gravity (as in satellite motion), (ii) the force of friction (as in a car

rounding a curve), or (iii) a force exerted by a string (motion in a

horizontal circle).

5. In the case of motion in a vertical circle, the force of gravity

provides the tangential acceleration and part or all of the

centripetal acceleration.

6. For the conical pendulum, the horizontal component of the tension

in the string provides the centripetal force.

7. In the case of a car rounding an unbanked curve, the force of static

friction is the central force.

8. When the curved roadway is banked at an angle, then the horizontal

component of the normal force is centripetal.

9. If a particle moves along a curved path in such a way that the

magnitude and direction of v change with time, the particle has an

acceleration vector that can be described with two component vectors.

10. The radial component vector arises from the change in direction of v ,

which is the centripetal acceleration, a_C = v²/r .

11. The tangential component vector is based on the change in magnitude

of v , and is usually found with the derivative dv/dt .

12. The total acceleration can be found with the vector sum of these two

accelerations which occur at right angles, so we use the Pythagorean

Theorem and inverse tangent.

13. 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.