Page 18 - text book form physics kssm 2020

Analysing Graphs to Summarise an Investigation
In general, there are fi ve important aspects in analysing graphs.

1
Recall
Th e relationship between two variables.
Gradient and
Method: intercept
Interpret the shape of graph obtained.

2
y
Th e gradient of the graph.
(xxx , yyy )
Method: 2 2
Δy 6y = yyy – y
Calculate the gradient of the graph, m = 2 1
Δx (x , y )
1
1
y – y
= 2 1 6x = xxx – x
x – x 2 1
2 1
0 x
3 y
Th e area under the graph.
y y y
2
Method: Area of triangle
Calculate the area under the graph using the y
1 Area of rectangle
relevant formula for the area.
0 x x x x x
1 2

y
4
Th e interpolation to determine the value of a 50
physical quantity. 40
30
Method:
If the value of x is given, determine the value of 20
y using interpolation and vice versa. 10
0 x
1 2 3 4 5

y
5
Th e extrapolation to make a prediction. 4 Line from
Method: 3 experimental
1. Extrapolate the graph. Extrapolation line 2 data
2. Determine the value of x or y concerned. 1 1 1
x
–5 –4 –3 –2 –1 0 1 2 3 4 5
Figure 1.9 Analysing graphs

12 12 1.2.2
1.2.2