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SECTION A Attempt ALL questions. You MUST write in this answer booklet. You must NOT spend more than 30 minutes on this section. 1. The apparatusshown in Figure I can be usedto determinethe accelerationdue to gravity.

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Electromagnet

Figure I As the electromagnet is turned off, the electric timer starts and the ball drops. When the ball hits the metal plate the timer stops. The ball falls through a distance of 65.0 cm before hitting the metal plate. The ball was dropped four times and the times were recorded as follows: T im e t o fa l l = 0 .3 6 1 s ; 0 .3 8 3 s : 0 .3 74 s: 0.365 s. (a) Determine the average of these results and write down the value of the time that should be used in calculations. Include an estimate of the uncertainty in this value.

[3 marks]

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(b)

Find the value for the acceleration to gravity from this experiment. due

[3 marks] (c) Distinguishbetween'systematic'and 'randomerrors'.

[2 marks]

(d) How might random errors be,reduced in this case?

[1 mark ] (e) Identify oNE sourceof a systematicerror in this experiment.

[1 mark I Total 10 marks

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-6L 2. by An oscillating system has a period, Z, which is related to the length, /, of the suspension the equation T = aln, where a and n are constants. Table I shows the time periods obtained as the length was changed.

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231

0.94

292 1.06

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515 1.42

859 1.86 ) )

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(a)

Plot a suitable graph using the axes on page 7 to allow you to determine the values of a and n.

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(b) Use the graph to find the value of n.

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[2 marks]

(c) Use your value of n to find a.

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[2 marks]

(d) Suggest an accuratemeans of determining the time period, Z.

[2 marks] Total 10 marks

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