physics
posted by Anonymous .
Suppose a ball of putty moving horizontally with 1kg.m/s of momentum collides and sticks to an identical ball of puffy moving vertically with 1 kg.m/s of momentum. Why is their combined momentum not simply the arithmetic sum, 2 kg.m/s?

Vector sum of two vectors at right angles
p=sqrt{p₁²+p₂²} =sqrt2 =1.41 kg•m/s