Term 3 Revision Test Answers
1. Base SI Units
metre (m) measures length
kilogram (kg) measures mass
second (s) measures time
Kelvin (K) measures temperature
Ampere (A) measures electrical current
candela (cd) measures light intensity
mole (mol.) measures amount of substance
2. Base SI Units are the original seven units decided upon in Paris. Derived SI Units are units that come from the Base Units, and can be made in two different ways. Firstly, I could add a prefix to a Base SI Unit to create a derived unit (millimetre), or I may combine base units to make a derived unit. (e.g. metres per second).
3. Error of parallax – can be avoided by keeping my eye perpendicular to the point I’m measuring.
Zero Error – I can make sure that I begin measuring from zero.
Worn away Ruler – I can measure from another mark, but must subtract that point from what I’m measuring.
4. A = l x b
= 20 metres x 8 metres
= 160 square metres
The pool has a surface area of 160 square metres.
5. V = l x b x h
= 20 metres x 8 metres x 20 decimetres
= 200 decimeters x 80 decimetres x 20 decimeters
= 320 000 cubic decimetres
As 1 cubic decimetre = 1 litres, 320 000 cubic decimetres = 320 ooo litres.
6. Absolute Zero is the coldest possible temperature, and is also the point where an object has no energy.
7. Absolute Zero on the Celcius (centigrade) scale is – 273 degrees Celcius (centigrade)
8. Scientists use Kelvin rather than Celcius (centigrade) scale because we know ice has a temperature, and in the real world you cannot get less than nothing.
9. a) weight = mass x gravity’s pull
= 48 kg x 10 N
= 480 N
Dennis’ weight is 480 Newtons.
b) Dennis’ mass on Earth is 48 kilograms.
c) weight = mass x gravity’s pull
= 48 kg x 1,667 N
= 80,016 N
Dennis’ weight on the Moon is 80,016 Newtons.
d) Dennis’ mass on the Moon is 48 kilograms.
conacher 