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Alternative a
Question 1
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(a) Diagram
You are provided with three retort stands, a pendulum bob, drawing board, stop-watch and other
necessary apparatus. Using the diagram above as a guide, carry out the following instructions:
(i) Fix the drawing paper on the drawing board and hold the board with two clamps such that
its vertical.
(ii)Suspend the pendulum bob such that it hangs freely in front of the drawing appear.
(iii) Draw a line RP representing the rest position of the pendulum string and mark the
position P of the centre of the pendulum bob at rest.
(iv) Displace the pendulum bob to one side in a plan parallel to the drawing board.
(v) Mark the new position p1 of the centre of the bob
(vi) Measure and record the perpendicular distance, d of pi from the line RP.
(vii) Evaluate and record d2•
(viii) Measure and record the vertical height h of p1 above P.
(ix) Evaluate G =d2/h
(x) Repeat the procedure for four other oppositions of p1
(xi)tabulate your readings
(xii) remove the drawing board so that the pendulum bob can swing freely.
(xiii) Set the pendulum bob oscillating through a small amplitude and determine the time t for
20 oscillations
(xiv) determine and record the period T.
(xv) plot a graph with G on the vertical axis and h on the horizontal axis, starting both axes
from the origin (0, 0).
(xvi) Determine the intercept 1 on the horizontal axis.
(xvii) Evaluate A = 1/(19.7)2
(xviii) State two precautions taken to obtain accurate results
(Attach your drawing paper to your answer booklet).
(b) (i)Distinguish between the period and frequency of oscillation of a simple pendulum.
(ii) Differentiate between oscillatory and rotational motions.
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This was fairly popular question with many candidates. However, most candidates did not perform
well.
Majority of the candidates did joint work; those that did not, could not complete traces or did the
traces poorly. Some did not even attach their traces. Some of the candidates with traces finds if
difficult to measure the distance d and height, h.
The evaluation of A = (1)/19.7T2 was a problem to few candidates.
Part (b)(i) was well answered by most of the responding candidates.
Part (b )(ii). Some candidates defined circular motion instead of the rotational motion demanded by
the question.
You are provided with three retort stands, a pendulum bob, drawing board, stop-watch and other
necessary apparatus. Using the diagram above as a guide, carry out the following instructions:
The expected answers are:
- OBSERVATION (11)
(i) Five complete traces showing positions of P and pi
(deduct 1/2 mark for each missing position of P1)
Score zero if P is not shown.
(ii) Five values of d correctly determined and recorded in em to at
least 1 decimal place.
(iii) Five values of d2 correctly evaluated to at least 3 significant figures
(iv) Five values of h correctly determined and recorded in em to at 1 decimal
Place and in trend.
(Trend: As d increases h increases)
(v) Five values of G correctly evaluated to at least 3 significant figures.
(vi) Value oft for 20 oscillations correctly determined and recorded in seconds
to at least 1 decimal place.
(vii) Value of T correctly determined and recorded in seconds to at least 2 decimal places.
(vii) Composite table showing at least d, d2, hand G.
Note: 1. lfno traces attached, award zero for (i) - (iv).
II. 1ft is recorded more than once, accept the first value only.
GRAPH [06]
(i) Both axes correctly distinguished ~ mark each
(ii)Reasonable scales ~ mark each
(iii) Five points correctly plotted
(iV)Line of best fit
Note:If origin not shown, deduct 1 mark for d.i.
INTERCEPT (01)
Intercept I on the horizontal axis
correctly shown
correct read
EVALUATION (01)
Correct substitution of A = 1/19.7T2
Correct arithmetic
PRECAUTIONS [02]
Award 1 mark each for any 2 correct precautions:
e.g
Conical oscillation avoided,
Draught avoided during oscillation
Parallax error avoided when reading the metre rule/stop watch
Zero error noted and corrected for on the stop watch/rule.
Neat traces.
(Accept any other valid precautions).
(b)(i)
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