Question

Between the two stations, a train accelerates uniformly at first, then moves with constant velocity and finally retards uniformly. If the ratio of the time taken is 1:8:11:8:1 and the maximum speed attained be 6060 km/h, then what is the average speed over the whole journe

Answer 1

As it turns out, the ionosphere reflects certain frequencies of radio waves. So the waves bounce between the ground and the ionosphere and make their way around the planet. The composition of the ionosphere at night is different than during the day because of the presence or absence of the sun.