Posted by john on Tuesday, November 8, 2011 at 9:15am.
Two cars leave the same point at the same time, each travelling at the same constant speed and each having the same mass. The first car drives directly east, while the second car heads directly north. If the centre of mass of the twocar system is travelling at 51 km/h (i.e. the magnitude of the velocity), how fast is each car travelling in km/h?

physics  drwls, Tuesday, November 8, 2011 at 10:18am
The CM moves diagonally NE at a speed that is the individual car speed multiplied by sqrt2. The individual car speed is therefore 51*0.707 = 36 km/h