Question

object 1 is moving in the positive x - direction. it collides with a second object that is initially at rest. the collision is not head - on, so the objects move off in different directions after the collision (see figure). what must be true about the total momentum of object 1 and object 2 in the y - direction after the collision?

the total momentum in the y - direction after the collision will point in the negative y - direction, because object 1 has a greater speed after the collision.

the total momentum in the y - direction after the collision will be equal to zero.

the total momentum in the y - direction after the collision will point in the positive y - direction, because object 2 has a greater mass.

Explanation:

According to the law of conservation of momentum, in the absence of external forces (assuming no external forces act in the \(y\) - direction), the total initial momentum of the system in a particular direction is equal to the total final momentum of the system in that direction. Initially, object 1 is moving along the \(x\) - direction (\(p_{1y,i}=0\)) and object 2 is at rest (\(p_{2y,i} = 0\)). So, the initial total momentum of the system in the \(y\) - direction \(P_{y,i}=p_{1y,i}+p_{2y,i}=0\).

Answer:

The total momentum in the \(y\) - direction after the collision will be equal to zero.