Page 10 - Pra U STPM 2021 Penggal 1 - Physics

Physics Term 1 STPM Chapter 2 Kinematics

Exam Tips
Note the difference between graph (a) and graph (b) when t = 0.
v v

2

0 t 0 t
(a) (b)
Initial velocity u = 0 Initial velocity u ≠ 0
Gradient at t = 0 is zero. Gradient at t = 0 is not zero.

Velocity-time Graph

1. Informations that can be deduced from the velocity-time graph:
(a) The instantaneous velocity.
t 2
(b) Between the time t = t 1 and t = t 2 , displacement = ∫ v dt = shaded area under the graph.
t 1
dv
(c) The acceleration, a = = Gradient of graph.
dt
(d) How the acceleration changes with time from the shape of the graph.
2. Figure 2.5 shows the velocity-time (v-t) graphs for various types of motion.
(a) v (b) v (c) v
u

u

0 t t t 0 t t t 0 t t t
1 2 1 2 1 2
Uniform acceleration. Uniform deceleration. Increasing acceleration.
Gradient = constant Constant negative gradient Gradient increasing

(d) v (e) v

0 t 0 t
t t t t
1 2 1 2
Decreasing acceleration. Constant velocity
Gradient decreasing
Figure 2.5 Velocity-time graphs

39

02 STPM PHY T1.indd 39 4/9/18 8:19 AM