Question

The table below shows the values of extensions of a spiral spring when various forces are applied to it.

Force F, (N)	0	1.2	2.0	3.0	4.0	5.0	6.0
Extension R, (cm)	0	0.8	1.5	2.3	3.1	3.8	4.6

1. On the grid provided, plot a graph against the extension.
2. From the graph, determine the work done in stretching the spring by 4cm.

Answer 1

1.  
   1. S1 L1 P2 L1
   2. P_o = 100kPa 
   3. slope = 180 – 110
                        8-1
      70 = 10kPa/m
       7
      10 x ϑ= slope
      10ϑ= 10KPa/m
      ϑ= 10Kpa/m
           10
      ϑ= 1KPa 

Answer 2

1. 
   
2. Work done = ½ ke² (where k is the spring constant)
   K = F/e = gradient = 130N/m (from the graph) 
   = ½ x 130 x 0.04²
   W = 0.104J