Example 2

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Pupils might choose to test the distance the bail has fallen.

Using this starting point, time that the bat tip has been past the crease line is constant and the distance that the bail has fallen is varied.  

In lesson 2 pupils will have calculated the time that the bat tip has been past the crease-line. A reasonable result is 0.095 s.  Pupils will also have calculated the distance that the lower bail has fallen. A reasonable result is 0.133 m. Reasonable limits for the distance that the bail has fallen would be 0.1 m and 0.2 m. Times for the bail to fall distances between these limits can be calculated using a spreadsheet and the formula  .

 

Fall of the Bail (m)

0.1

0.11

0.12

0.13

0.14

0.15

0.16

0.17

0.18

0.19

0.2

Time of fall (sec)

0.143

0.150

0.156

0.163

0.169

0.175

0.181

0.186

0.192

0.197

0.202

 

The spreadsheet formulas are as follows:

 

For THIS speed of the batsman and distance of the bat, the batsman is always OUT. This is because, in each case, the bail has been falling longer than the time the bat is assumed to have been past the crease line (0.095 s).

 

If you start with a different speed, there may be results where the batsman would be IN.

If the speed of the batsman is assumed to be 5 m/s and the distance that the bat tip is past the crease line is 0.95 m, then the time that the batsman has been past the crease-line is

 

For THIS speed of the batsman and distance of the bat, the batsman is IN for bail distances of 0.1 m - 0.17 m. In these cases, the bail has been falling for less time that the bat is calculated to have been past the crease line (0.19 s).