21st May 2016
Prof. Henrich Focke, a German inventor, devised the first practical helicopter called the Focke-Wulf Fw 16, which was successfully flown in 1936. By 1938 it set many world records for altitude, speed and flight duration. It could be flown by a pilot after only one hour of pilot briefing.
6th May 2016
A raindrop falls on the earth with varying speeds depending on its size and weight. The gravity acts on the falling raindrop and the drop picks up speed. But due to air resistance, which is generally proportional to the velocity, the raindrops attain a terminal speed. A larger raindrop would fall much faster at 9 metres per second whereas a smaller raindrop will fall at a much slower speed of 2 metres per second.
3rd May 2016
Andromeda, the galaxy closest to the Milky Way, is about 2.5 million light years away. To travel in space, we need to achieve the speed of light, which is about 3,00,000 kilometres per second. Even at that great speed, it will take us about 2 million years (not 2.5 million years due to an effect called time dilation) to reach Andromeda.