7 In ancient time the earth was believed to be a flat disc

Last updated: 6/12/2023

7 In ancient time the earth was believed to be a flat disc of uniform thickness Here we adopt the same model and describe the earth as a flat disc of radius sufficiently large say more than 40000 km Mass density is uniform and is equal to p The disc rotates about a stationary axis through its centre and perpendicular to its plane Period of rotation equals one earth day Universal gravitational constant is G The centre of the disc is the North Pole and circular edge is the South Pole All radial lines on the disc are the longitudes and all concentric circles are the latitudes Direction along a latitude in the direction of rotation is the East a If acceleration due to gravity at the North Pole is go what should thickness of the disc be b A shell is fired from the ground with velocity u at an angle with the longitude containing the place of firing How far from this longitude will the shell hit the ground c A shell is fired from the ground with velocity u at an angle with the latitude containing the place of firing How far from this latitude will the shell hit the ground