The sum of the heights of transmitting and receiving antenae in the sight of communication is h. Prove that the range is maximum if the two antennae have a height of `h/2` each.

A stone thrown at an angle theta to the horizontal reaches a maximum height h . The time of flight of the stone is

A projectile is thrown at angle beta with vertical . It reaches a maximum height H. The time taken to reach the highest point of it's path is

An Airforce plane is ascending vertically at the rate of 100 km/h. If the radius of the Earth is r km, then how fast is the area of the Earth visible from the plane increasing at 3 min after it started ascending ? Given that the visible area A at height h is given by A = 2pi r^(2) (h)/(r + h) .

A stone is projected vertically up to reach maximum height h. The ratio of its kinetic energy to its potential energy at a height (4h)/5 will be

Two balls have the same size but one is denser than the other. Assume the air resistance to be same on each, show that when they are released simultaneously from the same height, the heavier ball will reach the ground first.