The diagram illustrates the only two horizontal forces acting on a trolley, which is accelerating at $0.12\,\text{m s}^{-2}$. Calculate the mass of the trolley.
- A$0.050\,\text{kg}$
- B$0.13\,\text{kg}$
- C$20\,\text{kg}$
- D$80\,\text{kg}$
Physics 5054 · O Level · Balanced and unbalanced forces