(a) (i) and (ii)
A suspended
object will always stop so that its centre of mass is directly below the point
of suspension.
The pendulum
bob is a symmetrical object and so the centre of mass must be on an axis of
symmetry. For a circle it will always be at the centre of the circle. The
position of the stationary pendulum bob is clearly marked and supported with a
well-explained reason.
(b) The frequency would halve.
Inversely
proportional means more than simply ‘as one quantity increases the other
quantity decreases’. If two quantities are inversely proportional, when one
doubles the other will halve.
(c) (i) Hertz
This
could also have been given in symbol form (Hz). However, if you use symbols
make sure they are correct. Hz gets a mark but hz would not.
(ii) time
period, T = 22 ÷ 10 = 2.2 s
= 0.45 Hz
The
other values for frequency have been rounded to one decimal place so it would
be okay to round this answer to 0.5.
(iii) No
it does not support the hypothesis. If the hypothesis were correct then
doubling the length from 0.5 m to 1.0 m should make the frequency go
from 0.7 Hz to 0.35 Hz and it does not.
Marks
are not awarded for simply saying yes or no. In this case 1 mark is given for a
relevant calculation supporting the ‘no’. The answer could equally have used
the example of doubling the length from 0.25 m to 0.50 m.
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