There are two angles of projection for which horizontal range is the same. Show that product of their time of flights is directly proportional to the horizontal range?
The angles of projection, for which horizontal range is same, are θ and 90° – θ.
Time of flight for angle of projection θ is,
Time of flight corresponding to angle of projection (90°–θ) is,
Now, product of their time flight is,
Hence proved the relation.