# Momentum/velocity/position graphs

## Homework Statement

Two identical gliders are floating at rest on an air track. Glider 1 is given a quick push in the positive x-direction towards glider 2. When they hit, they stick together. The graphs below describe some of the variables associated with the motion as a function of time . The graphs begin recording data just after the push of glider 1 is completed.

Given the experiment as described above: for each of the items below, identify which graph, if assigned the appropriate scale, could properly describe the given variable as a function of time. Each graph may be used once, more than once, or not at all. If none of the graphs shown describe the quantity in question, record (J) as your response.

1.) The net force on glider 1
2.) The momentum of glider 2
3.) The position of glider 1
4.) The net force on glider 2
5.) The velocity of glider 1
6.) The total momentum of the system (consisting of both gliders)

## The Attempt at a Solution

For number 3, i thought the position of glider 1 would be graph E, since the glider is on a frictionless surface

for the other 5 questions, i really cant visualize it. im just not any good with graphs

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## Answers and Replies

Yeah, you are right about the position, but I don't follow your comment about the surface being frictionless relating.

You should focus on the easiest parts first, which to me would be momentum. What is the momentum of the first car? How about the second? Since momentum is always conserved, what is the system momentum - does it relate to the first car, the second car, or both?

Two of the graphs looks like they have equal magnitudes, but are negative, what physical law would that describe?