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5 An IGCSE student has carried out a timing experiment using a simple pendulum. She plotted _For a graph of T ²/s² against l /m. T is the time for one swing of the pendulum and l is the length _Examiner’s

of the pendulum. The graph is shown below.^Use

               T 2 / s2   

l /m

 (a) (i) Determine the gradient G of the graph. Show clearly on the graph how you obtained the necessary information.

                                                                                              G =  ......................................................

(ii)       Calculate the acceleration g of free fall using the equation

4π2

g =   . G

                                                                                               g =  ...............................................m/s²

(iii)     The student could have calculated the acceleration of free fall g from just one set of readings. State the purpose of taking sufficient readings to plot a graph.

 ..................................................................................................................................

 ..............................................................................................................................[5]

           © UCLES 2008                                                               0625/06/M/J/08

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            (b) The student next studies the relationship between the mass m of the pendulum and the _For

time for one swing T. The readings are shown in Table 5.1.Examiner’s

Use

Table 5.1

(i)       Suggest two variables that must be kept constant to make the experiment a fair

test.

1.   ..............................................................................................................................

2.   ..............................................................................................................................

(ii)     Study the readings in the table and complete the following sentence.

Within the limits of experimental accuracy, the readings show that the mass m of

the pendulum  .......................................................................................................[3]

                                                                                                                                               [Total: 8]

           © UCLES 2008                                                               0625/06/M/J/08