A train engine increases the speed of a train with total mass $800$ tonnes ($1$ tonne $= 1000\,\text{kg}$) from rest until it reaches $50\,\text{m s}^{-1}$. What amount of work has to be done 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$2.0 \times 10^9\,\text{J}$