What science is/is not and how physics and chemistry are connected

Will you chech and finish these for me, because i am stumped with them.

Considering only the earth's rotation, determine how much later the asteroid would have had to arrive to put the explosion above helsinki at longitude 25˚ e? this would have obliterated the city.

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?