GCSE · Compound units & rates

Converting compound units and rates of flowExam-style questions

Why converting a compound unit means converting both of its parts, where the ÷3.6 between km/h and m/s comes from, why g/cm³ to kg/m³ is ×1000, and how rates of flow work.

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13 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAll Level 2 Level 3 Level 4 Level 5

1
Convert 54 km/h into m/s.
Level 3 · 3 marksTry it
2
Convert 8 m/s into km/h.
Level 3 · 2 marksTry it
3
The speed limit on a UK motorway is $65$ mph on a stretch with roadworks.

Using $5$ miles $= 8$ km, convert $65$ mph into km/h.
Level 3 · 2 marksTry it
4
Concrete has a density of $2400$ kg/m³.

Convert this density into g/cm³.
Level 3 · 2 marksTry it
5
The diagram shows a water tank.The tank is a cylinder with radius $45$ cm and height $80$ cm.

The tank is full of water.

Water flows out of the tank through a tap at a constant rate of $12$ litres per minute.

$1$ litre $= 1000$ cm³

Work out how long it takes for all of the water to flow out of the tank.

Give your answer in minutes, correct to the nearest minute.

You must show all your working.

(4 marks)
Level 3 · 4 marksTry it

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