Two cars drive down the highway. the lead car has a constant velocity of 72 km/hr and is 50 km head of the trailing car that's going 80 km/hr. how much time does the trailing car need to catch up ?

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?