The earth's field departs from its dipole shape substantially at large distances (greater than about 30.000 km). What agencies may be responsible for this distortion?

A car and a truck are going on a straight road each having a velocity of 72 km/h. The car cannot come to a stop in less than 3.0 sec and the truck takes 5.0 seconds time to stop on the high-way. The car is behind the truck. The truck gives a signal for stopping at a tollplaza. What should be the least distance of the car from the truck so that it does not bump onto the truck? (Take human response time to be 0.5 sec)

Earthquakes generate sound waves inside the Earth. Unlike gases, the Earth can experience both transverse and longitudinal sound waves. Typically the speed of S wave is about 4.0 kms^(-1) and that of P wave is 8.0 kms^(-1) . A seismograph records P and S waves from an earthquake . The first P waves arrives 4 min before the first S wave. Assuming the waves traveling straight line, at what distanc does the earthquake occur ?

The moon is about 3,84,000 km from the earth, and its path around the earth is nearly circular. Find the speed at which it orbits the earth, assuming that it orbits the earth in 24 hours. (Use pi = 3.14 ).