Dr. J's Maths.com
Where the techniques of Maths
are explained in simple terms.

Measurement - units of energy related to people.
Test Yourself 1.


 

Conversion of units.  
   
   
   
Energy for mass and nutrition  
   
   
   
Energy expended in activities.

7. The table below shows the average energy used, in kilojoules per kilogram of body mass, by a person walking for 30 minutes at different speeds.

Walking speed KJ used in 30 mins.
3 km/h 5.53 kJ/kg
5 km/h 7.37 kJ/kg

Ben, who weighs 65 kg, drinks a regular coffee made with full cream milk. It contains 73 kilocalories.

For approximately how long must Sam walk at 3 km/h to burn off the energy contained in the cappuccino? (1 kilocalorie = 4.184 kJ)

Answer.25.5 minutes - say 26 minutes.
  8. Sutarman uses 85 kilocalories of energy during each kilometre he runs.

He prepares before he runs by eating two Classic Triple with Cheese burgers which each contain 970 kilojoules of energy.

How many kilometres will Sutarman have to run to use up the energy he gained from his two burgers? Answer correct to one decimal place (i.e. to the nearest 100 metres).

(1 kilocalorie = 4.184 kilojoules).

Answer.5.5 km.