two cars collide at an icy intersection and stick together afterward. the first car has a mass of 1300 kg and was approaching at 7.00 m/s due south. the second car has a mass of 800 kg and was approaching at 23.0 m/s due west. (a) calculate the final velocity of the cars. (note that since both cars have an initial velocity, you cannot use the equations for conservation of momentum along the x-axis and y-axis; instead, you must look for other simplifying aspects..) magnitude