Saturday, January 21, 2012

MEASURING AND USING NUMBERS
MENGUKUR DAN MENGGUNAKAN NOMBOR
By
Mohd Hanafiah B Said


1.   Figure 1.1 shows how to measure the length of a pencil.

     (Rajah 1.1 menunjukkan cara mengukur panajang pensil)
Figure 1.1

(a) Mark ‘X’ in the box provided on Figure 1.1 to show the correct position of the eye in taking the reading.
(Tandakan ‘ X ‘ dalam petak yang disediakan dalam Rajah 1.1 untuk menunjukkan kedudukan mata semasa mengambil bacaan)                                                                                                          [1 mark]

(b) What is the length of the pencil ?
     ( Berapakah panjang pensil itu ? )
____________________________________________________________[1 mark]

(c) A student wants to find the length of a curve as shown in Figure 1.2. 
     ( Seorang pelajar hendak mengukur panjang  garis lengkung dalam Rajah 1.2 )
Figure 1.2

(i ) What would he use to measure the length of the curve 
     ( Apakah yang perlu digunakan oleh pelajar tersebut untuk mengukur garis  
     lengkung ? )
        _____________________________________________________________  [1 mark]

Reading / Bacaan
1
2
3
Length / Panjang (cm)
12.5
12.7
12.6
 (


TABLE 1.3

(ii) Table 1.3 shows the results of the activity. What is the circumference of the  beaker
          ( Jadual 1.3 menunjukkan keputusan aktiviti. Berapakan ukurlilit bikar ? )
______________________________________________________________[1 mark]
    (iii) Why did the student take three readings ?  
         ( Mengapa pelajar itu mengambil tiga bacaan ? )
        ______________________________________________________________ [1 mark]
2.   Figure 2.1 shows an activity carried out by a student to find the thickness of a beaker.
     ( Rajah 2.1 menunjukkan aktiviti yang dijalankan oleh pelajar untuk mengukur ketebalan bikar )





Figure 2.1

(a)     Name the measuring tools, P and Q.
       ( Namakan alat pengukur yang digunakan, P dan Q )

(i)       P : ___________________________________________________________

(ii)     Q :_____________________________________________________  [2 marks]
  

     the beaker ?    
     ( Rajah 2.2 menunjukkan bacaan yang diambil oleh P. Berapakan panjang diameter
      dalam bikar itu ? )

Figure 2.2
  _____________________________________________________________  [1 mark]

(c)  Figure 2.3 shows the reading taken by Q. What is the length of the external diameter of the beaker ?
      (Rajah 2.3 menunjukkan bacaan yang diambil oleh Q. Berapakah bacaan     diameter dalam bag bikar itu ? )



Figure 2.3
______________________________________________________________[1 mark]

(d) Calculate the thickness of the beaker.
    ( Kira ketebalan bikar tersebut )
[2 marks]
3.    Figure 3 shows a measuring cylinder.
     ( Rajah 3 menunjukkan selinder penyukat )
Figure 3
(a)      Label the meniscus on Figure 3.1.
       ( Labelkan meniscus pada rajah 3.1 )                                                        [1 mark]

(b)     Put a (√) in the correct box on Figure 3.1 to show the correct eye position when
        taking a reading.
  ( Tandakan  (√) dalam petak pada Rajah 3.1 untuk menunjukkan kedudukan 
   mata yang betul bila mengambil bacaan )                                               [1 mark]

(c)      What is the volume of water in the measuring cylinder in Figure 3.1 ?
( Berapakah isipadu air dalam selinder penyukat dalam Rajah 3.1 ? )
_______________________________________________________           [1 mark]


(d)   Figure 3.2 shows how a measuring cylinder is used to find the volume of a stone.                                     
      (Rajah 3.2 menunjukkan mengukur isipadu batu menggunakan selinder penyukat )





(i)  Name the method shown in Figure 3.2 to find the volume of a stone.
    (Namakan kaedah yang digunakan dalam rajah 3.2 untuk menentukan isipadu 
     batu )

________________________________________________________ [1 mark]

(ii)       Calculate the volume of the stone.
        ( Kirakan isipadu batu itu )




[2 marks]

4.  Figure 4.1 shows an object, X. ( Rajah 4.1 menunjukkan objek X )




(a)  Based on the given data, calculate the density of object X.
( Berdasarkan data yang diberikan,kirakan ketumpatan objek X )


Volume of object X = 10 cm3
( Isipadu objek X )
Mass of object X     =  35 g
(Jisim objek X )
 
   



[2 marks]

(b)  Figure 4.2 shows a beaker containing a liquid, Y.
     ( Rajah 4.2 menunjukkan sebuah bikar yang mengandungi cecair Y )
(i)    On Figure 4.2, draw the position of X if it is dropped into liquid Y which has a  
     density of 1.3 g/cm3.
     (Pada rajah 4.2,lukiskan kedudukan X jika dijatuhkan ke dalam cecair Y  
     dengan ketumpatan 1.3 g/cm3.  __________________________________________________________[1 mark]
         (ii) Explain your answer in (b)(i).  
             ( Terangkan jawapan dalam  ( b )( i)
____________________________________________________________[1 mark]
(c)     Which of the following uses the principle of density? Tick (√) the correct answer in the box provided.
(yang manakah berikut menggunakan prinsip ketumpatan. Tandakan (√)  dalam petak yang disediakan )


















 
[1 mark]
5.  Figure 5 shows a student climbing up a flight of stairs.
    ( Rajah 5 menunjukkan seorang pelajar menaiki tangga )

(a)        Name the forces acting on the student.
         (Namakan daya yang bertindak ke atas pelajar itu )

(i)          ___________________________________________________________

(ii)     _____________________________________________________[2 marks]

(b)        Calculate the work done by the student if his mass is 45 kg.
                      [Consider that the gravitational force acting on a mass of 1 kg is 10 N]
                      (Kirakan kerja yang dilakukan oleh pelajar jika jisimnya ialah 45 kg . )
    [Anggaplah daya graviti yang bertindak   ke atas jisim 1 kg ialah 10 N ]








  
 [2 marks]

(c)  The student took 20 seconds to walk up the flight of stairs. State the formula to calculate power and calculate the power of the student.
     (Pelajar itu mengambil masa 20 saat untuk menaiki tangga. Nyatakan formula untuk mengira kuasa dan kirakan kuasa pelajar tersebut.)









[3 marks]
6.  Figure 6.1 shows a type of lever.
     (Rajah 6.1 menunjukkan sejenis tuas.)




(a)     Label the following words on Figure 6.1.
       ( Labelkan perkataan-perkataan berikut pada Rajah 6.1 )


Effort


Load

Fulcrum
[3 marks]
(b)(i) State the class of the lever shown in Figure 6.1.  
     (Nyatakan kelas tuas pada Rajah 6.1 )

         __________________________________________________________[1 mark]
     (ii) Give one reason for your answer in (b)(i).
         (Berikan satu sebab bagi jawapan (b) ( i )   
        ___________________________________________________________[1 mark]
           
(b)     Figure 6.2 shows Daniel and Amy on a see-saw.
(Rajah 6.2 menunjukkan Daniel dan Amy di atas jongkang-jongkit)
(i)    If the see-saw is in equilibrium, who has a bigger mass ?
     (Jika jongkang –jongkit dalam keseimbangan,siapakah yang mempunyai 
      jisim yang lebih besar ? )
         ______________________________________________________________[1 mark]

           (ii) Explain your answer in (c)(i).  
                (Terangkan jawapan anda dalam ( c )( i  ))

                __________________________________________________________[1 mark]

(d)     Based on the data given, calculate Amy’s weight. (Berdasarkan data diberikan,kira berat Amy )

Daniel’s weight =
(Berat Daniel)
400 N
                 X      =
1.5 m
                 Y      =
2.0 m
 
 



[2 marks]
7.       Figure 7 shows a 3-pin plug. (Rajah 7 menunjukkan palam 3-pin )





(a)     On figure 7, label P, Q and R using the following words. (Labelkan Rajah 7 dengan perkataan berikut:)

Neutral wire/ Dawai neutral


Earth wire / Dawai bumi

Live wire / Dawai hidup
             [3 marks]
(b)     What is the function of X ?  ( Apakah fungsi X ? )

________________________________________________________________

________________________________________________________________                         [1 mark]

(c)     Give one advantage of a 3-pin plug. (Berikan satu kebaikan palam 3-pin )

________________________________________________________________

________________________________________________________________                         [1 mark]

(d)     State the formula and calculate the current flow in an electric kettle labelled  1 500 W and 240 V.
      (Nyatakan formula dan kirakan arus yang mengalir dalam cerek elektrik yang 
      berlabel 1 500 W dan 240 V )
            





[3 marks]

(e) Which of the following is a suitable fuse for the electric kettle in 7(d)?
     Circle the correct answer.
     (Berikut yang manakah nilai fius yang sesuai untuk cerek elektrik dalam 7 (d)?.Bulatkan jawapan yang sesuai)


5 A


10 A

13 A

[1 mark]



JAWAPAN
ANSWERS (USING NUMBERS)
(b) 5.3 cm

(c) Thread and ruler

(d) 12.6 cm

(e) To get a more accurate reading

2.     (a)  (i) Internal calipers

(ii) External calipers



 
(b) 1.8 cm

(c) 2.0 cm

(d)      2.0 cm – 1.8 cm
              2

 =  0.1 cm


3.      
(c) 46 cm3
(d) (i) water displacement method

     (ii)  Volume of stone  =  63 – 46 cm3

                                       = 17 cm3

  1. (a)  Density of X =    35 g
                                     10 cm3
      
                                   =  3.5 g/ cm3


(b) (i)









      
  (ii) Object X is denser than liquid Y // Liquid Y is less dense than object X. 
    (c)
















5.     (a)  (i) Frictional force

 (ii) Gravitational force

(b) Work done =  (45  X 10) N  X  5 m

                        = 2 250 J

(c) Power = Work done
                       Time

                = 2 250 J
                      20 s

                = 1 12.5 W



(6) (a)
  (b) (i) First class lever

(ii) The fulcrum is between effort and load // The fulcrum is in the centre

(c) (i) Daniel

(ii) X is shorter than Y // Y is longer than X//Daniel sits closer to the fulcrum

(d)         400 N X 1.5 m = X  X 2.0 m
                  
                              X = 400 N X 1.5 m
                                          2.0 m

                              X  = 300 N

  1. (a) P: Live wire
           Q: Neutral wire
           R: Earth wire

(b) Breaks the circuit when there is excess current flowing through it

(c) Prevents the electrical appliance from being damaged by excess current // Sends the leaked current (from the body of the electrical appliance) to the Earth

(d) Current flow     =  Power
                             Voltage

                         = 1 500 W
                               240 V

                         = 6.25 A

 (e)

5 A


10 A

13 A


                          


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