Recent content by MattGeo

Do you mean by just calculating the impulse starting at the collision instant and incorporating both masses since they're effectively a single mass at that point?

I am not sure why it never occurred to me before despite actually having taken an advanced classical mechanics course in college, but how do we treat a collision where the objects involved are actually accelerating? In the case where colliding objects move at constant velocity it is standard...

I wanted to bring up the deformation and elasticity because isn't it necessary anyway for the interaction? We treat objects as rigid but if they actually were fully rigid wouldn't that prevent the Coulombic interaction as they encroach on each other? There's a nonzero interaction in the EM...

So say that two objects collide in an elastic collision. They have different masses and are made of different materials. Upon collision they each deform to some extent and store elastic energy before rebounding. Being that they are different materials with different molecular lattices I imagine...

I spend a lot of time thinking about collision problems because for me they are both extremely interesting and often very difficult to grasp when one thinks about them beyond the basics we are taught in introductory or even intermediate university courses. Suppose there is a perfectly elastic...

If I accelerated by using the excellent first and then I apply the same force to the surface after already moving, how could the energy be the same as having just pushed off the surface first with the same force. I guess it's conceptually a stumbling block in the first place that prevents me...

I don't really understand why the first mechanism results in a fixed increase in KE and the second mechanism results in a fixed acceleration. Could you elaborate on that? How are they "fixed" and how are they different?

So I was wondering something new after this problem that you elucidated for me finally clicked. How is this situation related to (or unrelated to) the Oberth Effect? Like suppose a car were traveling in a situation where there was zero air resistance and we could safely ignore internal...

I was curious about this part here. Why did you say that in the moving frame the car goes from -10m/s to 0 and then to 10m/s?

Wow thank you, this was a great and helpful response.

The last thing you said makes sense to me but I am not sure how to apply it in this situation. If we consider the 2 cars moving at 10 m/s relative to the ground, but at rest to each other, and 1 of them accelerates from rest in that frame to 10 m/s, that is a greater amount of fuel used than...

Say 2 cars are traveling side by side at 10 m/s in some flat, wide open space. Relative to each other they are stationary. Relative to someone on the ground they are both moving at 10 m/s. Now say you're in 1 of the cars and you see the other car accelerate, changing his velocity by 10 m/s in...

Alright. but how can it be an equilibrium situation if the weight of water in my 12 inch straw is so much less than the weight that atmospheric pressure can support when it counters gravity? Take the mercury barometer as an example. The tube is filled with mercury. But THEN the mercury level...

The mercury is heavy enough to draw an actual vacuum though if you fill a tube, close it, and invert it. A column of mercury is raised approx 760 mm under atmospheric pressure near sea level. Water would be raised about 33 feet under the same conditions. So that is part of what confuses me. A 12...

For quite a long time I had just gone by the traditional explanation that when you place a straw vertically into water without fully submerging it and then you withdraw the straw from the water, the water column stays inside because the pressure from the atmosphere acting on the bottom of the...