Question

Sphere x, of mass 2 kg, is moving to the right at 10m/s. sphere y, of mass 4 kg, is moving to the left at 10m/s. the two spheres collide head-on. the magnitude of the impulse of x on y is:

Answer 1

20m/s, honestly I have know idea what the asnwer is but if i had to guess, this would be my answer.