Assume that the earth is not rotating about its axis and that Scientists have developed an engine which can propel vehicles to very high speed on the surface of the earth. What is the maximum possible speed for any such vehicle running on surface of the earth. Earth is a sphere of radius R = 6400 km and acceleration due to gravity on the surface is `g=10m//s^(2)`

Answer

`V_(0)=sqrt(gR)=7.9km//s`