SPM Practice 3 (Linear Law) – Question 1


Question 1 (10 marks):
Use a graph to answer this question.
Table 1 shows the values of two variables, x and y, obtained from an experiment.
The variables x and y are related by the equation y h = hk x , where h and k are constants.


(a) Plot xy against x, using a scale of 2 cm to 1 unit on the x-axis and 2 cm to 5 units on the xy-axis.
Hence, draw the line of best fit.

(b) Using the graph in 9(a), find
(i) the value of h and of k,
(ii) the correct value of y if one of the values of y has been wrongly recorded during the experiment.

Solution: 
(a)




(b)
y h = hk x xy h x=hk xy= h x+hk Y=mX+C Y=xy, m= h , C=hk


(b)(i)
m= 36.5 5.1 h = 36.5 5.1 h =7.157 h=51.22 C=4 hk=4 k= 4 h k= 4 51.22 k=0.0781


(b)(ii)
xy=21 3.5y=21 y= 21 3.5 =6.0 Correct value of y is 6.0.