Page 72 - Hybrid PBD KSSM 2021 Tg 4 - Fizik

Fizik Tingkatan 4 Bab 2
4. Rajah di bawah menunjukkan graf halaju-masa bagi suatu objek yang bergerak.
The diagram below shows a velocity-time graph for a moving object. SP 2.2.2 TP3 KBAT Mengaplikasi
Halaju, v / m s –1
Velocity

25

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0 Masa, t / s
30 70 85 105 120 Time

–10

Berdasarkan graf tersebut, hitung / Based on the graph, calculate
(i) jumlah masa objek tersebut berada dalam keadaan pegun.
the total time the object is at rest.
t = 105 – 85 = 20 s
(ii) pecutan objek pada 30 saat pertama.
the acceleration of the object during the first 30 seconds.

a = 25 – 0 = 0.83 m s –2
30 – 0
(iii) nyahpecutan objek tersebut dari t = 70 s sehingga t = 85 s.
the deceleration of the object from t = 70 s until t = 85 s.
a = 0 – 25 = –1.67 m s –2
85 – 70
∴nyahpecutan / decleration = 1.67 m s –2
(iv) jumlah jarak yang dilalui oleh objek tersebut.
the total distance travelled by the object.
 1   1 
a = 2 × 25 × (40 + 85) + × 10 × (120 + 105)
2
= 1562.5 + 75
= 1637.5 m

(v) jumlah sesaran yang dilalui oleh objek tersebut.
the total displacement travelled by the object.
 1   1 
a = 2 × 25 × (40 + 85) + × 10 × (120 + 105)
2
= 1562.5 + 75
= 1487.5 m
(vi) laju purata bagi objek tersebut.
the average speed of the object.
v = 1637.5 = 13.65 m s –1
120
(vii) halaju purata bagi objek tersebut.
the average velocity of the object.

v = 1487.5 = 12.40 m s –1
120

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02 HYBRID PBD FIZIK F4.indd 31 05/11/2021 8:20 AM