A workman moves a barrel, whose weight is $2000\,\text{N}$, up a plank that is $2.0\,\text{m}$ long and into a lorry. The back of the lorry stands $0.80\,\text{m}$ above the horizontal road surface. What work is done on the barrel against gravity?
- A$1000\,\text{J}$
- B$1600\,\text{J}$
- C$2500\,\text{J}$
- D$4000\,\text{J}$