Answer:
The puck B remains at the point of collision.
Step-by-step explanation:
This is an elastic collision, so both momentum and energy are conserved.
The mass of both pucks is m.
The velocity of puck B before the collision is vb.
The velocity of puck A and B after the collision is va' and vb', respectively.
Momentum before = momentum after
m vb = m vb' + m va'
vb = vb' + va'
Energy before = energy after
½ m vb² = ½ m vb'² + ½ m va'²
vb² = vb'² + va'²
Substituting:
(vb' + va')² = vb'² + va'²
vb'² + 2 va' vb' + va'² = vb'² + va'²
2 va' vb' = 0
va' vb' = 0
We know that va' isn't 0, so:
vb' = 0
The puck B remains at the point of collision.