A roller-coaster goes over a 12 m tall hill then approaches a 25 m hill. What is the minimum velocity the roller-coaster would need when going over the 12 m hill to make it to the top of the 25 m hill?

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?