What hours in the day are covered by AM ?

AM is the time between midnight (12am) and midday (12pm).

How many days are there in a year ?

There are 365 days in a normal year and 366 days in a leap year .

True or False? An analogue clock works in 24 hours time.

False. An analogue clock works in 12 hour time .

What hours in the day are covered by PM ?

PM is the time between midday (12pm) and midnight (12am).

True or false? To convert between two metric units of measure, you must multiply or divide by powers of 10 .

True. To convert between two metric units of measure, you must multiply or divide by powers of 10 . E.g. to convert from centimetres to metres, divide by 100.

What type of quantity is measured using cubic units?

Cubic units are units used to measure volume .

True or False? To convert between cubic units, you must multiply or divide by the normal unit conversion rate .

False. To convert between cubic units, you must multiply or divide by the 'cubed' conversion rate . E.g. to convert from cm 3 to m 3 you must divide by 100 3 .

What type of units are used to measure area ?

Square units are used to measure area .

True or False? To convert between square units, you must multiply or divide by the 'squared' conversion rate .

True. To convert between square units, you must multiply or divide by the 'squared' conversion rate . E.g. to convert from km 2 to m 2 you must multiply by 1000 2 .

Define the term compound measure .

A compound measure is something calculated using more than one measurement , e.g. speed is calculated using distance and time.

True or False? Flow rate is an example of a compound measure .

True. Flow rate is an example of a compound measure . It combines two measures (volume and time) by looking at the volume of fluid that moves over time, (e.g. cm 3 / s).

Define the term population density .

Population density is the measure of how many people there are per unit of area .

True or False? When using a formula triangle with a compound measure, you can add the two values at the base of the triangle to find the value at the top of the triangle.

False. When using a formula triangle with a compound measure, you need to multiply the two values at the base of the triangle to find the value at the top of the triangle.

A journey has two parts, each covered at a different speed. Why can you not find the average speed for the whole journey by averaging the two speeds?

Average speed is total distance divided by total time , and the two parts of the journey usually take different lengths of time. Averaging the two speeds treats them as equally important, which is only correct when the two parts take exactly the same time.

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Standard & Compound Units (Edexcel IGCSE Maths B): Flashcards

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What hours in the day are covered by AM?

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Cards in this collection (28)

What hours in the day are covered by AM?
AM is the time between midnight (12am) and midday (12pm).
What is the equation that converts minutes to hours?
The equation that converts hours to minutes is $Hours = Minutes \div 60$ .
How many days are there in a year?
There are 365 days in a normal year and 366 days in a leap year.
True or False?
An analogue clock works in 24 hours time.
False.
An analogue clock works in 12 hour time.
What hours in the day are covered by PM?
PM is the time between midday (12pm) and midnight (12am).
What is the equation that converts hours to minutes?
The equation that converts hours to minutes is $Minutes = Hours \times 60$ .
How many hours are there in one day?
A day has 24 hours.
How many days are in a week?
There are 7 days in a week.
True or false?
To convert between two metric units of measure, you must multiply or divide by powers of 10.
True.
To convert between two metric units of measure, you must multiply or divide by powers of 10.
E.g. to convert from centimetres to metres, divide by 100.
What is the equation used to convert kilometres to metres?
The equation used to convert kilometres to metres is:
$Metres = Kilometres \times 1000$ .
What is the equation used to convert millilitres to litres?
The equation used to convert millilitres to litres is:
$Litres = \frac{Millilitres}{1000}$ .
What is the equation used to convert kilograms to milligrams?
The equation used to convert kilograms to milligrams is:
$Milligrams = Kilograms \times 1, 000, 000$ .
What type of quantity is measured using cubic units?
Cubic units are units used to measure volume.
True or False?
To convert between cubic units, you must multiply or divide by the normal unit conversion rate.
False.
To convert between cubic units, you must multiply or divide by the 'cubed' conversion rate.
E.g. to convert from cm³ to m³ you must divide by 100³.
What type of units are used to measure area?
Square units are used to measure area.
True or False?
To convert between square units, you must multiply or divide by the 'squared' conversion rate.
True.
To convert between square units, you must multiply or divide by the 'squared' conversion rate.
E.g. to convert from km² to m² you must multiply by 1000².
Define the term compound measure.
A compound measure is something calculated using more than one measurement, e.g. speed is calculated using distance and time.
True or False?
Flow rate is an example of a compound measure.
True.
Flow rate is an example of a compound measure.
It combines two measures (volume and time) by looking at the volume of fluid that moves over time, (e.g. cm³ / s).
Define the term population density.
Population density is the measure of how many people there are per unit of area.
True or False?
The units of a compound measure can be used to find the equation needed to calculate it.
True.
You can use the units of a compound measure to find the equation used to calculate it.
For example, speed is often measured in km / h.
Km (kilometres) is a measure of distance and h (hours) is a measure of time, so the calculation for speed is:
$Speed = \frac{Distance}{Time}$
True or False?
When using a formula triangle with a compound measure, you can add the two values at the base of the triangle to find the value at the top of the triangle.
False.
When using a formula triangle with a compound measure, you need to multiply the two values at the base of the triangle to find the value at the top of the triangle.
Complete the two formulae for these compound measures.
$density = \frac{______}{volume}$
$pressure = \frac{force}{______}$
The completed formulae are:
$density = \frac{mass}{volume}$
$pressure = \frac{force}{area}$
Both are 'per' measures, so density is mass per unit of volume and pressure is force per unit of area.
What kind of speed does $speed = \frac{distance}{time}$ actually give you?
It gives the average speed for the whole journey, not the speed at any particular moment.
A car covering $120$ km in $2$ hours has an average speed of $60 km/h$ even if it was never travelling at exactly that speed.
A journey has two parts, each covered at a different speed. Why can you not find the average speed for the whole journey by averaging the two speeds?
Average speed is total distance divided by total time, and the two parts of the journey usually take different lengths of time.
Averaging the two speeds treats them as equally important, which is only correct when the two parts take exactly the same time.
The density of gold is $19.3 {g/cm}^{3}$ and a gold bar has a mass of $0.454$ kg. What must you do before using the density formula?
Convert the mass into grams, so that it matches the units the density is given in.
Here $0.454 kg = 454 g$ , and dividing by a density in ${g/cm}^{3}$ then gives a volume in ${cm}^{3}$ .
True or False?
A pressure of $1 {N/m}^{2}$ and a pressure of $1$ pascal are the same thing.
True.
The pascal (Pa) is simply another name for a newton per square metre.
So $1 Pa = 1 {N/m}^{2}$ , and a pressure may be written either way.
Why can you not put an object's mass straight into $pressure = \frac{force}{area}$ ?
The formula needs a force, and the force an object exerts because of gravity is its weight, not its mass.
Mass measures how much matter an object contains, so mass and weight are different quantities measured in different units.
A box exerts a force of $140$ N on a table and the pressure on the table is $35 {N/m}^{2}$ . What units will the contact area have?
The area will be in square metres, $m^{2}$ .
The pressure is measured in newtons per square metre, so the area that goes with it has to be measured in square metres.

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