Page 16 - Focus TG4 KSSM (Physics) Terbitan Penerbitan Pelangi Sdn Bhd

Physics Form 4 Chapter 2 Force and Motion I

Q2 A bus travelled along a straight road and stopped Q4 A lift travelled up from the ground floor to the fifth
at ‘Bus Stop 1’ to pick up some passengers. It floor. It stopped for a while before moving down
then continued its journey until it stopped at ‘Bus and then finally stopped at the first floor.
Stop 2’. The v-t graph in Figure 2.34 shows its
motion.
Bus stop 1 Bus stop 2

v / m s –1

20
15 Velocity

10 4
Chapter
2 5 2
0 10 20 30 40 50 60 t / s 0 5 10 15 20 Time
–2
Figure 2.34
(a) How far did the bus travel before it stopped – 4
at ‘Bus Stop 1’?
(b) For how long did the bus stop at ‘Bus
Stop 1’? Figure 2.36
(c) Calculate the deceleration of the bus before (a) (i) When did the lift stop at the fifth floor?
it stopped at ‘Bus Stop 2’. (ii) Explain your answer in (a)(i).
(d) Find the distance between ‘Bus Stop 1’ and (b) (i) For which period of time did the lift travel
‘Bus stop 2’.
down?
Q3 The s-t graph in Figure 2.35 shows the (ii) Explain your answer in (b)(i).
displacement, s, of a boy from his classroom (c) Calculate the total distance travelled by the
along a corridor. lift when it finally stopped at the first floor.
s / m (d) Calculate the displacement of the lift at t = 20 s.
35
Physics of 100 m World Record
30 The v-t graph of Usain Bolt when breaking the
100 m record in Berlin in 2009
25
v / m s –1
20
12
15
10
10
8
5
6
0 5 10 15 20 25 30 35 40 45 50 55 t / s
4
Figure 2.35
2
(a) (i) What is the total distance travelled by the
boy? 0 t / s
(ii) Calculate the average speed of the boy. 2 4 6 8 10
(b) Halfway along the corridor, he stopped to
pick up some books that he had dropped Q5 Without doing the actual calculation, what is the
accidentally on the floor. When was the time, area under the v–t graph shown above?
t, he picked up the books?
(c) Sketch the v-t graph from t = 0 to 55 s.

32

02 FOC PHYSICS F4 3P.indd 32 29/01/2020 1:39 PM