ST Pretest 3.6
1. a)
The diagram is missing one way that CO2 is removed from the
atmosphere. Name it.
Rain can remove carbon dioxide by forming carbonic acid.
CO2 + H2O  H2CO3
b)
What role does respiration play in the carbon cycle?
It returns carbon to the atmosphere in the form of carbon dioxide:
C6H12O6 + 6 O26 CO2 + 6 H2O
c)
Is it always true that trees also rely on respiration, but overall, their
photosynthetic rate is greater than respiration?
Yes, provided that they are growing.
2. A kettle’s efficiency is 75%. If it wastes 2500 kJ of
energy, how much of the energy is useful and used to
boil water?
(x - 2500)/x = 0.75, where x = total energy
x – 2500 = 0.75x
x – 0.75 x = 2500
0.25 x = 2500
x = 10 000 kJ
useful = 10000 – 2500 = 7500 kJ
3. In a hot water tank, there are a couple of ways to improve efficiency. One way
is shown in the diagram. a) What have they done to improve it?
They added insulation to the sides of the tank.
b) What else can be done (not shown)?
Insulate the hot water outlet.
Questions 4 and 5 below only have 1 answer.
4. B…..2(causes wind) and 4
5. B ( this is part of thermohaline circulation)
Questions 6 and 7
Make sure you know how to do pages 139 and 145 in the study guide.
8.
In a belt and pulley transmission system, how are the rotational directions
related to each other? (There is a mistake in the second description of the
pulley and belt on p148 of the study guide)
The belt and both wheels all turn in the same direction.
9.
Between a gear train and a belt and pulley, which one is less likely to involve
slippage?
The gear train –gear’s teeth sink in between those of the other gear.
10.
Between the (1) chain-sprocket, (2) wheel-worm gear, (3) gear train and (4) belt
and pulley, which is not reversible? (meaning that switching input and output is
not easy)
wheel-worm gear,
Finally be prepared to view a new movie and answer questions based on it.