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Measurements and Units
Cells and Functions
Forces 1
Forces 2
Ecology
100

It contains a number and a unit

physical quantity

100

Basic unit of life.

cell

100

True or False

Weight is a force.

True

100

The value of the gravitational field strength of Earth is .................

10 N/kg

100

The main source of energy in an ecosystem is the ..........

sun

200

Numbers written using powers of ten are called .................

scientific notation

200

An outer membrane found only in plant cells to keep it in shape.

cell wall

200
Quantities that have a magnitude and a direction are called .................

vector quantities

200

TRUE or FALSE.

When two or more objects act on each other, their total momentum remains constant, provided no external forces are acting.

TRUE

200

The role of an organism in an ecosystem is called .............

niche

300

Air in the room has a density of 1.3 kg/m3. What is the mass of air measuring 5m x 2m x 3m?

39 kg

300

Cells that possess a membrane-bound organelle is called a .................... cell

eukaryotic/ eukaryote

300

The upward force from a liquid or a gas that makes some things float.

upthrust

300
Calculate the moment of a 4N force applied 3.5 m away from the pivot.

14 Nm

300

Name one way on how energy is lost as it is passed along a food chain. 

Any of the following: heat, respiration, faeces, an organism is not consumed entirely.

400

If an irregular solid is too big for a measuring cylinder, what can be used to find its volume?

displacement can

400
A specialised cell that is important in transporting oxygen in the bodies of mammals.

red blood cell

400

A skydiver is falling at a steady velocity where the forces involved are balanced. At this point the skydiver's speed does not anymore increase. What do you call the state where the skydiver is in?

terminal velocity

400

The moment (turning effect)  of a force depends on two factors. What are they?

magnitude of force and perpendicular distance from the pivot

400

The topmost part of the food pyramid is occupied by which organisms? 

apex predator

500

Give the SI units of the following:

length, mass, volume, temperature, time

metre, kilogram, cubic metre, Kelvin, seconds

500

A group of cells which specialises in the same function or activity are called ...............

tissues

500
The relationship between force, mass and acceleration represented by the formula: resultant force = mass x acceleration is related to what Newton's law?

Newton's second law of motion

500

The wind pressure on the wall is 100 Pa. If the wall has an area of 6 m2, how do we find amount of force?

F = p x A or Force = pressure x area

500

What is the scientific term that is used to describe plants as the producers in a food chain?

autotrophs