a
Weight
of pen
Weight
= mg seen or used
[ignore
power of 10 error]
Answer
[ 0.11 N]
Eg
Weight = 0.011 kg x 9.81 m s-2
=
0.108 N
2
marks
bi
Add
labelled arrow to represent weight
Arrow
pointing down at 8 cm labelled
weight (of pen) /0.11 N /W/mg /their
value
[Check
by eye. Arrow will be along the vertical line of the last letter ‘d’ in the
word
‘balanced’ in the line above]
1
mark
bii Calculate
weight of top(ecf their value of weight)
Use
of principle of moments i.e. a clockwise moment equal to an anti-clockwise
moment
[Give
this mark even if distances are wrong, but must use 0.11 N / their value]
Correct
distances used [must be 1 cm and 4cm, no ECF from bi]
Answer
[ 0.03 N ]
Eg
0.11 N x 1 cm = W
x 4 cm
W = 0.0275 N
[Only
penalise same unit error once]
3 marks
