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 Physics Paper 1, MAy/June. 2007
 Questions: 1 2 3 4 5 6 Main

Weakness/Remedies
Strength

Question 1

You are provided with a retort stand, clamp and boss, a pendulum bob, a piece of thread and other necessary apparatus. Carry out the following experiment:

(i)set up apparatus as shown in the diagram above;
(ii)measure and record the distance centre L = 130cm from the centre of the bob to the point of suspension of the pendulum;
(iii)displace the pendulum through a small angle and release, allow the pendulum to oscillate freely;
(iv)determine the time t for 20 complete oscillations;
(v)also, determine the period T of the oscillations;
(vi)evaluate T2 and L = l – 30;
(vii)repeat the procedure for four other values of I = 110, 90, 70 and 50cm;
(viii)in each case determine t and evaluate T, T2 and L.

(ix)plot a graph of T2 on the vertical axis against L on the horizontal axis, starting both axes from the original (0,0);
(x) determine the slope, s, of the-graph. Also determine the intercept, C, of the graph on the T2 axis;
(xi)evaluate:
I.k1 = 4/s пr2 [ Take п =22/7 ]
II.k2 = c/5;
(xii)state two precautions taken to ensure accurate results.

(b)(i)What is meant by the period of oscillation of an oscillating body?     [21 marks]
(ii)Explain acceleration of free fall due to gravity.                                  [21 marks]

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Observation

The candidates were required to:

(i)set up experiment as shown in the diagram above;
(ii)measure and record five values of time t to at least 1 decimal place in seconds and in trend.

Trend: t decreases as 1 decreases;

(iii)evaluate five values of period T correctly and record to at least 2 decimal places;
(iv)evaluate five values of T2 correctly and record to at least 3 significant figures .
(v)record data in a composite and complete table showing l, L, t, T and T2
(vi)indicate the graph axes; select reasonable scales, plot the five points correctly and draw a line that best fits the point;
(vii)read ΔT2 and ΔL and also evaluate ΔL/ ΔT2
(viii)show intercept on the vertical axis, read and record its value;
(ix)correctly evaluate k1 and k2 to get a value for k1 = g as supplied by the teacher;
(x)state any two of the following precautions in acceptable form of speech:
•I avoided conical oscillations.
•I ensured firm suspension of pendulum.
•I ensured reading is repeated (shown on the table).
•I avoided draught.
•I corrected for zero error of metre rule/stop clock.
•I avoided parallax error in reading metre rule/stop clock.

(b)(i)The period of oscillation of a body is the time taken for the body to make one complete to and from movement.

(ii)When a body is falling under its weight (alone), the rate of increase of its velocity with time (as a result of the earth's gravitational pull) is the acceleration of free fall due to gravity.

This question required candidates to show their competence in .timing the movement of a pendulum bob. Evidence of repeating readings (which was not mentioned in the question) is a first point required of the candidates. From the total for making 20 oscillations many candidates failed to show evidence of how to calculate the period of oscillation as total time for 20 oscillations divided by the number of oscillations.
The lack of comprehension of this is exhibited in the candidates inability to give correct and acceptable definition to the Period of oscillations in the short answer part of the question.