Collisions in two dimensions is a difficult section to read and understand. But, when we look at momentum similarly to our 'Sum of our Forces', then we can use the same concept to solve these problems. This means that the momentum in the x direction before the collision has to be as the momentum after the collision. The momentum in the y direction before the collision has to be as the momentum after the collision. 1. True2. False

Question

Emmanuel

Physics

10 November, 06:47

Collisions in two dimensions is a difficult section to read and understand. But, when we look at momentum similarly to our 'Sum of our Forces', then we can use the same concept to solve these problems. This means that the momentum in the x direction before the collision has to be as the momentum after the collision. The momentum in the y direction before the collision has to be as the momentum after the collision. 1. True2. False

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Lily Lee · Answer 1

2. True

Explanation:

Since momentum is a vector, you, indeed, in two dimension collisions, you can decompose it in two components, the x-direction and the y-direction, such as you do with the force, which is a vector too.

The law of conservation of momentum states that the total momentum before and after the collision are conserved.

Let's assume a collision in one dimension: x-direction.

If object A is moving to the right, its momentum is to the right. If objcet B is at rest its momentum is zero. Then, if when object A collides with object B, the first stops, the second must move to the right with a momentum in the x-direction equal to the momentum that object A initially had.

You can apply the same reasoning if object A is moving in two dimensions, and, a similar one, if object B is not at rest: at the end the momentum in each direction before the collision has to be equal to the momentum in each direction after the collision.