The last of the PSSLC's of 2003.

Next school year 2014-2015, we'll be witnessing the last batch of RBEC students graduating from the old Curriculum. The curriculas before it, as far as my memory can carry me were SEDP, NSEC, RBEC, BEC as well as SEC and the latest was ASEC. Now its K+12. The last two batches were warned that failing in this two year period would result to spiraling down to the K+12 and would entail additional years just to reach college. Then again, the students said if they enter Grades 11 and 12, they can already find jobs after it and are not in a hurry to enter college years. One can always outreason what others state as warnings (or heralds-depending on who is listening). 

The last batch of Physics curriculum had remained the same since it was introduced last 2003. The PSSLCs of the past 10 years, was itself an experimental set of LCs. If one were to study the Modules created for K+12 and the Prototype Lesson Plans of the 2003 PSSLCs, one can actually feel the the K+12 modules were "rehashed" versions of the 2003 Prototype Lessons. The Prototype Lesson Plans themselves show hallmarks of an amateur mind, with lots of ENCARTA, scanned comics and copied but uncited books that were more done haphazardly than products of longer research or studies. What does that tell me of the K+12? It feels like more of the same.

Why did I say that the 2003 PSSLC's were experimental? The lesson topics covered the REVERSED (Optics to Mechanics) topics of standard Physics textbook treatment (Mechanics to Optics). There was never an explanation as to why the reversal was done. It never served its purpose since College entrance tests always follow the Physics standard treatment of topics. When it was first shoved down to us, all Physics major teachers were in an uproar until we were told to Tow the line. Of course we never towed the line and opted to follow how college treat Physics since that would be the Physics that our students will eventually face.

THIS IS THE "DYING" PSSLCs of PHYSICS

https://docs.google.com/file/d/0B52LsZdeqWiFSWZiVDR3Y3R6Y28/edit?usp=sharing

Happy to share this to all of you.

K+12 PHYSICS FOR HIGH SCHOOL

The Physics Curriculum of K+12

The K+12 for high school (Grades 7 to 10) is spread-out over four years of high school and taken by piecemeal. Based on my understanding of the K+12 curriculum, the idea was to train high school teachers for teaching the K+12 Physics and by Grade 10, it will be spiraled. The teachers then will teach all year levels but by quarters, depending on the schedule. But the way some administrators and their consultants have understood the K+12, they only send First year teachers (usually GenSci Majors) where they learn all 4 subjects -Chemistry, Biology, Physics and Earth Sciences in one week seminars. According to feedbacks, some of these teachers didn't teach the subjects at all (Physics especially).. This could lead to a serious implication that by fourth year (Grade 10) the students will have to deal Physics according to actual Physics major teachers at Grade 10 and will be discussing higher levels of Physics where the students arriving at their Grade 10 levels don't know Physics at all. 

Luckily I got copies of the hand-outs and DepEd and managed to collect all the Physics LC.s and objectives into one Physics "curriculum." 

The K+12 Physics Objectives and LCs 

The collected LC's can assist all Pinoy Physics teachers waiting (or already undergoing) training for K+12. Any changes before Grade 10 arrives can be freely done because its a spreadsheet. This can easily tell a Physics Teacher how to construct their Lessons.

I hope this can help. Enjoy downloading.

The First Law of Motion - Newton's First Law of Motion


A typical answer to this one is "An object at rest or in constant motion tends to remain in that state unless an outside force acts to change such state". 
Simple and easy to recall but the generalized statement reduces the concept associated with such a statement. When I lecture about this Law, the divide it into two with the second statement further subdivided to two.

Newton's First Law of Motion

1. An object at rest tends to remain at rest unless a net force acts to make it move.

• An object in constant velocity will remain in such state of motion unless a net force acts to change that constant velocity.
• An object in constant angular velocity will remain in such state unless a net torque acts to change the constant angular velocity.

Work, Work, Work

One of the things that a teacher encounter in a classroom are the misconceptions developed and even reinforced over the years. As 4th year teacher, I need to let them change their vehemently held ideas. One of them is the concept of Work. Defined by a student when called to recall it from their elementary and early high school, they recite this mantra: Work is  Force times distance of W=Fd . FALSE of course for several reasons.

1. Work is a scalar quantity, so it cannot be a product of a vector (Force) and scalar (distance). The result of such multiplication is a vector quantity. 
2. The multiplication used is a dot multiplication not algebraic multiplication and so must be expressed as Work = F•d.
3. The other factor is NOT distance but displacement. The dot product of displacement (Vector) and force (Vector) is Work (Scalar).

The usual equation given in books is W = Fdcosθ. This equation is the magnitude version of the above mentioned vector equation. The θ is the angle between the Force F and the displacement d and the usual angle between the two is 0º and the value of cosine zero (cos0º) is 1. The entire equation then simplifies to W = Fd, which is the magnitude version.


Furthermore, it is not always TRUE that when force causes motion, work is done. When Force causes motion that is perpendicular to its action [Cosine(90º)= 0], no work is also done. But that is the only instance it can happen. 


To some teachers also include the fact that Work is also the product of torque and angular displacement. W = Γθ. Here when a force acts on a body pivoted at a certain point, it spins and does not translate or change its position.

SPEED OF NEUTRINO

I have been watching YOUTUBE videos and reading e-BOOKS on latest Physics news. Of course the latest universe-shaking news was the possibility that NEUTRINOS (all flavors?) outrun PHOTONS. There were several conjectures as to the 3-year CERN experiment consistently showed that neutrinos outrun photons but the prospect of "disproving" special and general theory of relativity by this experiment is so daunting (Imagine... proving Einstein wrong in an experiment... Einstein also encountered the same dilemma when he proved Newton incorrect in a theory). Why is it daunting? Relativity has been the hallmark of understanding the universe and now all theoretical physicist are discussing every exotic idea to explain it. Maybe we don;t need to change relativity, just change "the speed of light" and change it to the "speed of neutrino" ?

Activity 2.2

Group Number:       _________________

Group Members:     _________________, ___________________, __________________, ____________________ ,

                                    _________________, ___________________, __________________, ____________________ ,

Activity Number:    2.2

Activity Title:           Projectile Motion

General Objective:             Gain understanding of the concepts of motion in two-dimensions

Specific Objectives:            (10 sessions)

1.1.                        Describe a projectile

1.2.                        Explain the motion of a projectile using coordinates

1.3.                        Differentiate semi-parabolic projectile from parabolic projectiles

1.4.                        Solve projectile problems using the principles of free-fall and the kinematical equations.

1.5.                        Cite applications of projectile motion.

Description:            

            This activity uses a demonstration-experiment on how projectile motion happens based on their understanding of acceleration and constant speed. Further explanation is given on motions in the text of the workbook to clarify further its meaning.

DIRECTION: Read the discussion, examples and fill-out the blanks on the tables given.

           

            Projectile

           

DEFINITION 2.2.1 missile or shell: an object that can be fired or launched by force.

Projectile Motion

           

           

DEFINITION 2.2.2 the motion or behavior exhibited by a projectile

            What objects exhibit projectile motion?

Projectile motion is exhibited by a body as it is propelled along its path. Below are illustrative examples of the motion of a projectile.

Anybody who has seen a ball shot in a basket in basketball games, or a football kicked such that it bounces up has seen a projectile in motion. All these motions are referred to as rectilinear motion or motion-in-two-dimensions. This motion happens to follow a parabolic trajectory. Due to the nature of forces acting on the object as it travels, the parabolic motion is the normal path of its travel. Examples of such motions besides thrown objects are shown below.

Fig. 2.2.1 A welder cuts holes through a heavy metal construction beam with a hot torch. The sparks generated in the process follow parabolic paths. Parabolic paths are paths of projectiles

Fig. 2.2.2 Pyroclastic eruptions of volcanoes are streams of lava projected upwards. The lava trajectory follows a parabolic path characteristic of a projectile.

 

Description of Motion

The motion of a projectile is best described in two separate equations. When a projectile is thrown, it must have two things in it: An initial velocity v_i and an angle of projection θ_i. A third requirement is time, in order to fully plot the trajectory of the projectile.

Fig. 2.2.3

These are as follows:

Motion along x-axis (along the ground)

                                          where                     EQ. 2.2.1

Motion along y-axis (upward and downward motion)

                                    where                     EQ. 2.2.2

            Q1: Determine the x and y positions of a stone thrown 30˚ above the ground with an initial speed of 60 m/s.  Use a separate sheet of bond paper to solve this problem.

Combining the motion of the two equations by eliminating the time t we come up with this typical x and y equation.

                       A typical parabolic equation   EQ. 2.2.3

            Q2. Derive the Equation 2.2.3 from 2.2.1 and 2.2.2. Use a separate sheet of paper to derive this.

           

            Q3: A ball is thrown in such a way that its initial vertical and horizontal components of velocity are 40 m/s and 20 m/s, respectively. Estimate the total time of flight and the distance the ball is from its starting point when it lands. Use a separate sheet of paper to solve this.

            Determining the Maximum Height and Maximum Range

                                   

Figure 2.2.4

A projectile fired from the origin at t_i = 0 with an initial velocity v_i. The maximum height of the projectile is h, and the horizontal range is R. At A, the peak of the trajectory, the particle has coordinates (R/2, h).

To obtain the maximum height of the projectile shown in Figure 2.2.4, we use this equation:

                        Maximum height equation     EQ. 2.2.4

            To obtain the maximum range (maximum horizontal displacement) of the projectile shown in Figure 2.2.4, we use this equation:

                      Maximum range equation      EQ. 2.2.5

            Q4: Derive the Equation 2.2.4 and 2.2.5 from Equation 2.2.3. Use a separate sheet to show this derivation.

            Q5: A long-jumper leaves the ground at an angle of 20.0° above the horizontal and at a speed of 11.0 m/s. (a) How far does he jump in the horizontal direction? (Assume his motion is equivalent to that of a particle.) (b) What is the maximum height reached? Solve this on a separate sheet of paper.

Figure 2.2.5

A projectile fired from the origin with an initial speed of 50 m/s at various angles of projection.

Note that complementary values of θ_i result in the same value of x (range of the projectile).

Q6: Prove by calculation that the maximum range of an object thrown at 50 m/s is 45˚. Compare its ranges with that of 75˚, 60˚, 45˚, 30˚, 15˚. Solve this on a separate sheet of paper.

                                                                        Figure 2.2.6

           

Q7: A stone is thrown from the top of a building upward at an angle of 30.0° to the horizontal and with an initial speed of 20.0 m/s, as shown in Figure 2.2.6. If the height of the building is 45.0 m, (a) how long is it before the stone hits the ground? Solve on a separate sheet of paper.