7/24/2019 Bi-filar Oscillations of Meter Rule;Moment of Inertia
Marks Scheme
1/2
1. (a) lcorrectly found to mm or better from average of l1and
l2[shown] (1)
Checked that separation of threads at top was also 40.0 cm (1)
0.03 s of Supervisors value from 30T(1)(1)
(1)
(1)
T
T
30froms05.0
10froms03.0
[0/2 if Tto nearest second][0/2 if Tnot shown i.e. 20T]
Repeat readings [shown] (1)Use of fiducial mark (pin) at centre
of oscillations [must be at centre] (1) 6
(b) Correct diagram of arrangement (1)
Distances shown clearly to centres of mass (1)All positions
recorded to mm or better from diagram or below (1)
Long lengths used (both 8 cm) or repeats shown (1)
Any good technique for centre of 50 g mass (1)Correct
calculation 2 / 3 significant figures + unit (1) [Max 5]
Value 2 g of Supervisors value (1)(1)
[ 4 g (1)] 7
(c) Correct S.I. substitution (1)Correct calculation (1)Unit (1)
3
[16]
Sample results
(a) l1= 49.0 cm, l2= 49.0 cm l= 49.0 cm
Checked that separation of threads at top was also 40.0 cm
20T/ s: 20.03, 20.13, 19.96
average T= 1.00 s
Repeat readings
Use of a fiducial mark (pin) at centre of oscillations
(b) Scale readings at centre of mass = 24.9 cm
50.0 46.5 35.1 24.9
0.050 g mg
x y
x=
2
5.460.50
35.1 cm
= 13.15 cm
y= 35.1 24.9 = 10.2 cm
mgy= 0.050gx
m=2.10
15.13050.0
= 0.0645 kg (64.5 g)
Khalid Mazhar Qureshi www.edexcel-cie.com
