Passengers in the jet transport $A$ flying east at a speed of 800 $\mathrm{kmh}^{-1}$ observe a second jet plane $B$ that passes under the transport in horizontal flight. Although the nose of $B$ is pointed in the $45^{\circ}$ north east direction, plane $B$ appears to the passengers in $A$ to be moving away from the transport at the $60^{\circ}$ angle as shown. Then what is the true velocity (in $\mathrm{km} / \mathrm{h}$) of $B$ ?

Question

Aicharya · Accepted Answer

According to law of sines or Lami's Theorem $\Rightarrow \frac{v_{A}}{\sin 75^{\circ}}=\frac{v_{B}}{\sin 60^{\circ}}=\frac{v_{B / A}}{\sin 45^{\circ}}$ $\Rightarrow v_{B}=717 \mathrm{kmh}^{-1}$ ~

Passengers in the jet transport $A$ flying east at a speed of 800 $\mathrm{kmh}^{-1}$ observe a second jet…

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