The discussion revolves around a problem in momentum involving a cart and an object dropped onto it. The original poster presents a scenario where a 2.4kg cart is moving at a constant speed of 2m/s when a 1.5kg object is dropped onto it, prompting questions about the change in momentum of the system.
Some participants express confidence in their calculations, while others seek clarification on the implications of mass increase on momentum. There is an exploration of whether the final answer being negative is appropriate in this context, indicating a productive dialogue about the underlying physics.
Participants are navigating assumptions about the conservation of momentum and the effects of mass on the system's speed and momentum change. There is a lack of consensus on the interpretation of the results, particularly regarding the sign of the momentum change.
the answer I've got is 1.8substance90 said:So what is the problem with this one? Seems perfectly ok to me.
Doc Al said:You need to find the momentum of the cart before and after the object drops onto it. You have the cart's speed before the collision, so you can find its initial momentum. But what is its speed after the collision?
Hint: What's conserved during any collision?
That happens to be correct, but how did you arrive at this answer?dh743 said:Thanks for your help but i ended up with the correct answer but negative (-1.8). Would this be correct in this situation?
Does the cart speed up or slow down?I would have thought an increase in mass (the object) would mean an increase in momentum.