Question

For saving energy, bicycling and walking are far more efficient means of trans- port than is travel by car. For example, when riding at 16 km/h, a cyclist uses food energy at a rate of about 1670 kJ/h above what he would use if merely sitting still. Walking at 5 km/h requires about 940 kJ/h. It is interesting to compare these values with the energy consumption required for travel by car. Petrol yields about 3.4x10'J per litre. The Volkswagen Golf VII petrol car achieves a fuel efficiency of around 4.2L/100km. The Hyundai Ioniq electric car achieves 15.7 kWh/100km. Find the fuel efficiency in kilojoules per kilometre of a) walking, b) cycling, c) the Golf petrol car and d) the Ioniq electric car.

Answer 1

answer & Given speed during waking = 5km/h and energy consuption which is & like fuel- efficiency/Consuption here Ep = 940 kJ/ since there are 940 kJ fuel efficiency for per- hour, but also there are 5km distance covered per hour. so fuel efficiency kI per kilometer - guo k /n fuel efficiency E= - - 5 km/h Ep = 940 kg Ep = 188 kW/km (fos walking) Auswer (b) Given speed during egt cycling = 16 km/h and pood energy consuption rate which is used here as fuel efficiency = 1670 kJ/h Now required fuel efficiency in kilojoules per kilometer - 1670 KJ/h = 104.37 kJ / (for cycling) Ep = / km 16 km/h

Auswen (0) Given petrol yield for Golf car = 3.48 10t / litre and fuel efficiency for Golf can- Ef = 4.2 L/100km there are 4.2 litre fuel consuption per 100 km and 3.4 x 107 Joules energy released by 1 litre petrol. So energy efficiency in kI per km - Ef = 4.2 L x 3.4x107 / 100km Ef = 1.42 x 100 J/km = 1.42 x 103 kJ m КМ Answer (d) Given fuel efficiency of Ioniq electric can- Ef = 15.7 kWh/lookm Since we know that - 1 klah = 3.6 x 106 Joules - 15.7 kWh x 3,68 106 Joules so Ef = - Too km Ep = 5.658 105 J/km ] [Ep = 565 kJ/km ] (for Ioniq electric car)