Explain why
Atmospheric pressure at a height of about 6 km decreases to nearly half of its value at the sea level, though the height of the atmosphere is more than 100 km

As you have learnt in the text, a geostationary satellite orbits the earth at a height of nearly 36,000 km from the surface of the earth. What is the potential due to earth’s gravity at the site of this satellite? (Take the potential energy at infinity to be zero). Mass of the earth = 6.0 xx 10^24 kg, radius = 6400 km

A train travels at a certain average speed for a distance of 63 km and then travels a distance of 72 km at an average speed of 6km/hour more than its original speed. lf it takes 3 hours to complete the total journey, what is its original average speed?

A TV tower has a height of 100m how much population is covered by the TV broadcast if the avarage population density around the tower is 1000km^-2?(given radious of the earth = 6.37*10^6 m )