Saturday, 18 February 2006

Fisika SMA

Pengalaman Belajar Fisika di SMAN BI 1 Banjar

Ada Apa Dengan Fisika?

Lesson Plan: Graphing Data from a Spreadsheet


SUBJECT: Technology
TOPIC: Presenting Data
DESCRIPTION: A set of problems dealing with graphing data.
CONTRIBUTED BY: Carol Hodanbosi
EDITED BY: Jonathan G. Fairman - August 1996

Purpose:
To graph real data to input into a computer spreadsheet
Objective:
To illustrate a distance versus time graph using student data from running various distances.
Materials:
  • computer spreadsheet with data from previous lab activity
  • computer graphing utility
Procedure:
  1. Each student will be graphing the average of their classes running speed data, putting distance (from 0 meters to 20 meters on the vertical or Y axis, and time on the X axis ( in seconds), in 0.1 second intervals.
  2. Plot the values for your class, using the average time for the 5, 10, and 15 meter distances.
  3. Plot a fourth point using a zero distance, and estimating what the time would be for that distance.
  4. Draw a straight, best-fit line through the data points.
  5. Using the points for the 15 meter time and the zero point as endpoints, calculate the slope of the line segment.
  6. What does the slope represent?
  7. Can you predict the slope of the line if the distance were extended to a much greater value, such as 10,000 meters (10k), or 40,000 meters?

A blank graph of distance versus time
Sumber:
NASA

Sunday, 1 January 2006

Astronomi

Astronomi, yang secara etimologi berarti "ilmu bintang" (dari Yunani: άστρο, + νόμος), adalah ilmu yang melibatkan pengamatan dan penjelasan kejadian yang terjadi di luar Bumi dan atmosfernya. Ilmu ini mempelajari asal-usul, evolusi, sifat fisik dan kimiawi benda-benda yang bisa dilihat di langit (dan di luar Bumi), juga proses yang melibatkan mereka.

Selama sebagian abad ke-20, astronomi dianggap terpilah menjadi astrometri, mekanika langit, dan astrofisika.

Astronomi ialah cabang ilmu alam yang melibatkan pengamatan benda-benda langit (seperti halnya bintang, planet, komet, nebula, gugus bintang, atau galaksi) serta fenomena-fenomena alam yang terjadi di luar atmosfer Bumi (misalnya radiasi latar belakang kosmik (radiasi CMB)).

Ilmu ini secara pokok mempelajari pelbagai sisi dari benda-benda langit seperti asal-usul, sifat fisika/kimia, meteorologi, dan gerak dan bagaimana pengetahuan akan benda-benda tersebut menjelaskan pembentukan dan perkembangan alam semesta.


Astronomi Bulan: kawah besar ini adalah Daedalus, yang dipotret kru Apollo 11 selagi mereka mengedari Bulan pada 1969. Ditemukan di tengah sisi gelap bulan Bumi, garis tengahnya sekitar 93 km
Astronomi adalah salah satu di antara sedikit ilmu pengetahuan di mana amatir masih memainkan peran aktif, khususnya dalam hal penemuan dan pengamatan fenomena sementara. Astronomi jangan dikelirukan dengan astrologi, ilmusemu yang mengasumsikan bahwa takdir manusia dapat dikaitkan dengan letak benda-benda astronomis di langit. Meskipun memiliki asal-muasal yang sama, kedua bidang ini sangat berbeda; astronom menggunakan metode ilmiah, sedangkan astrolog tidak.

1 Astronomi observasional
  • 2 Astronomi teoretis

  • 3 Cabang-cabang spesifik
  • Sumber:

    Wikipedia.

    Sunday, 18 December 2005

    Fisika SMA

    Pengalaman Belajar Fisika di SMAN BI 1 Banjar

    Ada Apa Dengan Fisika

    Experiment: Vector Addition by the Numerical Method


    SUBJECT: Mathematics
    TOPIC: Vector Addition
    DESCRIPTION: A set of problems dealing with vector addition.
    CONTRIBUTED BY: Carol Hodanbosi
    EDITED BY: Jonathan G. Fairman - August 1996

    Purpose:

    A vector is a quantity that has both magnitude, or size, and direction. Forces can be represented by vectors, since they have both a size and direction of action. Below is an example of a mass supported by two cables. If the mass is not moving, all the forces acting on the mass are considered to be balanced. You will investigate each of the forces acting on the mass and compare their relationships.

    Diagram of a weight suspended by two wires from a frame. Weight is labeled F.

    Fw represents the weight of the object. It is found by mulitplying its mass by gravity. That is, Fw = m * g, where g equals 9.8 m/s2. This force is directed downward.

    Exercises:

    1. If the object represented by F has a mass of 4.8 kilograms, find its weight.
      (answer)

    2. What direction is the weight of the object acting? Draw this vector through the center of mass of F .
      (answer)


    3. The lines CB and CA are vector quantities that are supporting and acting opposite the object F . Draw a line through point C parallel to the base support. Measure the angle between CB and the line just drawn.
      Since vectors CB and CA are not acting parallel or perpendicular to the base of the stand, it is helpful to find the components of each of these vectors. Components are vectors that combine vectorally to form the resultant vector, in this case CB or CA . For example, to find the components of CA or CB one first needs to find the angle that vector forms with the horizontal line, angle ACD or angle BCE , see diagram below.



      A vector diagram. C is the axis point, A is above C and 35 degrees to the left. B is above

 C and 35 degrees to the right. F is directly below C, D is below A, and E is below B. C,D and

 E form a straight horizontal line.

      To find components of vector CB , form a right triangle with CB as the hypotenuse. Since CB is a vector, or a ray, one will be selecting a fixed portion of CB . Recall the trigonometric functions of the sine (side opposite/ hypotenuse) and the cosine (side adjacent / hypotenuse). The sine of angle BCE would equal side BE/CB , while the sine of angle ACD = AD/ AC .
      Let's assume that the angle ACD and angle BCE are both 35° and that the weight represented by vector CF is 100 newtons. Since the weight is static, and not moving, we can assume all the forces are balanced. The vector represented by CE (to the right) must be balanced by the vector CD (to the left).The downward force of the weight represented by CF must be balanced by the two upward forces DA and EB . Since the two right triangles have two congruent angles (35°) and two congruent sides, (FD and CE ) the two triangle are congruent (Leg, Acute angle).
      Because DA + EB = CF then DA = EB = 50 newtons.

      By substitution, Sin angle BCE = BE/CB


      Sin 35° = 50/CB
      CB = 50 /Sin 35°
      CB = 87.17 newtons
      One can also find the measure of CE or CD using the tangent function.
      tan BCE = BE/EC
      tan 35° = 50 /EC
      EC = 50 /tan 35°
      EC = 71. 4 newtons


      Now use the following diagram to solve the problems below.
      A diagram of a weight suspended from a boom.
      A load of 500 kg is suspended at the end of a horizontal boom supported by a cable. The cable makes a 42° angle with the boom and is attached to a wall by a supporting pin. You can assume the boom's mass is negligible.
    4. Find the downward force vector (the weight of the mass).
      (answer)

    5. Represent the components of the cable (one is inward toward the wall, the other is upward, opposite the mass).
      (answer)

    6. Find the tension in the cable.
      (answer)

    7. Find the outward force of the boom.
      (answer)

    Sumber:

    NASA