A plane is travelling in a straight line at constant speed at an angle $\theta$ to the horizontal. The aeroplane experiences four forces: thrust force $T$, weight $W$, lift force $L$ and resistive force $R$. Which two equations must be true?
- A$L = W\cos\theta$ and $T = R + W\sin\theta$
- B$L = W\sin\theta$ and $T = R + W\cos\theta$
- C$L = W\cos\theta$ and $T = R - W\sin\theta$
- D$L = W\sin\theta$ and $T = R - W\cos\theta$