Recent content by Freaky Fred

This is very interesting, basically the ''same situation''. 😯

Let's assume this balloon is indestructible. I'm assuming a scenario where the air is denser than the balloon at rest, but the balloon at relativistic velocity is denser than air to the observer.

Hi, guys o/ Suppose a person sees a helium balloon moving horizontally at close to the speed of light. From this perspective, the observer will see the helium balloon contract in accordance with special relativity. If helium contracts to the point where it is denser than air, will it fall? how...

Really. Nature is a beautiful and complex puzzle. :smile:

Hello! First, Newton's second law. (mass m) F = ma -kx = ma ma + kx = 0 You can divide all by mass. a + kx/m = 0 We have a differential equation. d2x/dt2 + kx/m = 0 (Homogeneous) It was considered that the solution is of the type: x = ert This is a strategy to solve this kind of second order...

That was not what I meant. I wanted to write that the force that the leg applies to the foot have an intensity equal to the force that the foot applies to the leg. The force of the torso on the leg would be of lesser intensity, so that was the first forward movement. As I said in the second...

I really mixed up two ways of interpreting (sorry, again). What I really want to know is how this works considering the body as several parts (foot, leg, trunk, neck, head). I imagine that the force of the leg on the foot will be equal in intensity to the frictional force (so that the foot...

Oh sorry. A terrible mistake. But I can not understand why the foot does not slip if the resulting horizontal force is different from 0. I know that in a static regime there is no movement between the surfaces, but I can not understand how this happens if the result is not 0 on the foot.

Hello :smile: When we are walking, exist, basically, three forces on us foot.(gravity, normal and friction forces). Considering that the frictional force is in static regime, the resulting force is 0. Theoretically, there is no relative movement between the foot and the floor. So my doubts: How...