The sound of a cannon firing is heard one second later at a position $\mathrm{B}$ than at position $\mathrm{A} .$ If the speed of sound is uniform, then

• Correct answer
  A

  The positions $\mathrm{A}$ and $\mathrm{B}$ are foci of a hyperbola, with cannon's position on one branch of the hyperbola
• B

  the position $A$ and $B$ are foci of an ellipse with cannon's position on the ellipse
• C

  One of the positions $A, B$ is focus of a parabola with cannon's position on the parabola
• D

  It is not possible to describe the positions of $A, B$ and the cannon with the given information

Solution

$\mathrm{PB}-\mathrm{PA}=\mathrm{Vt}+\mathrm{v}-\mathrm{vt}$ $\mathrm{PB}-\mathrm{PA}=\mathrm{V}$ (const) locus of P is Hyperbola A \& B are foci of Hyperbola

Hence, the correct answer is option: 'A'.