2010 WAEC Physics Practical   You are provided with three retort stands, a pendulum bob, a drawing board, a stopwatch,...

2010 WAEC Physics Practical You are provided with three retort stands, a pendulum bob, a drawing board, a stopwatch,...

WAEC 2010

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You are provided with three retort stands, a pendulum bob, a drawing board, a stopwatch, and other necessary apparatus. Using the diagram above as a guide, carry out the following instructions.

Fix the drawing paper on the drawing board and hold the board with two clamps such that it is vertical.
Suspend the pendulum bob such that it hangs freely in front of the drawing paper.
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.
Displace the pendulum bob to one side in a plane parallel to the drawing board.
Mark the new position P\(^{1}\) of the centre of the bob.
Measure and record the perpendicular distance, d of P\(^{1}\) from the line RP
Evaluate and record d\(^{2}\).
Measure and record the vertical height h of P\(^{1}\) above P.
Evaluate G =\(\frac{d^{2}}{h}\)
Repeat the procedure for four other positions of P\(^{1}\).
Tabulate your readings.
Remove the drawing board so that the pendulum bo can swing freely.
Set the pendulum bob oscillating through a small bob amplitude and determine the time, t for 20 oscillations.
Determine and record the period, T.
Plot a graph with G on the vertical axis and h on the horizontal axis, starting both axes from the origin (0,0).
Determine the intercept I on the horizontal axis.
Evaluate A = \(\frac{1}{19.7T^{2}}\)
State two precautions taken to obtain accuratee 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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Explanation

S/N	d/cm	d\(^{2}\)cm\(^{2}\)	h/cm	G = d\(^{2}\)/n/cm
P\(_{1}\)	3.30	10.89	3.00	39633
P\(_{2}\)	5.50	30.25	2.80	10.80
P\(_{3}\)	7.60	57.76	2.60	22.22
P\(_{4}\)	9.60	92.16	2.40	38.40
P\(_{5}\)	10.50	110.25	2.20	50.11

Length Rp = 20cm

time taken = 21.76 seconds
n = 20
T = \(\frac{t}{n} = \frac{21.76}{20}\) = 1.088 seconds.

A = \(\frac{T}{19.7T^{2}}\)

A = \(\frac{3}{19.7 \times 1.088^{2}}\)

A = \(\frac{3}{23.320}\)

A = 0.1286cm/s\(^{2}\)

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Precautions;

- Parallax error avoided when reading the meter rule/stopwatch.
- Conical oscillation avoided.
- Draught avoided during oscillation.
- Zero error noted and corrected for on the stopwatch/rule
- Neat traces.

(b)

Period	Frequency
- It is the time taken to complete one oscillations/cycle (to and fro motion) - Unit is second(s)	- It is the number of complete oscillations in one second. - Unit is Hertz (Hz)

Oscillatory motion	Rotational motion
It's when a body moves in a to and fro manner (in a plane) Examples: Swing in motion pendulum in motion, vibrating string, loaded test tube, the vibration of tuning fork.	It's when a body turns about an axis, through the body. Examples: blades of a fan in motion, motion of the earth about its axis.