A railway engine increases the speed of a train with a total mass of 800 tonnes (1 tonne = 1000 kg) from rest until it reaches $50\,\text{m s}^{-1}$. What amount of useful work has to be carried out on the train for it to attain this speed?
- A$1.0 \times 10^{6}\,\text{J}$
- B$2.0 \times 10^{6}\,\text{J}$
- C$1.0 \times 10^{9}\,\text{J}$
- D$2.0 \times 10^{9}\,\text{J}$