I have made a funny homemade experiment, repeatable, and with a high success rate over 6 bottles of cola. I haven't found any trace on internet. It reminds me the Mentos-Diet Coke experiment, but I am focusing on the lemon. Take a bottle of sugarfree cola, e.g. diet Pepsi in this case. Cut a lemo...

Instead of the usual approach of integrating a bunch of discs, I do it differently. I integrate by subdividing the sphere into a bunch of concentric spheres containing mass on their surface. The integral becomes: $\int_0^R r^2 \cdot (4\pi r^2) \cdot \rho \space dr$ which ends up equaling $\frac{3...

The Question: An object of mass $5\, \mathrm{kg}$ is projected with a velocity $20\, \mathrm{ms}^{-1}$ at an angle $60^{\circ}$, to the horizontal. At the highest point of its path, the projectile explodes and breaks up into two fragments of masses $1\, \mathrm{kg}$ and $4\, \mathrm{kg}$. The fr...

In “A Brief History of Time”, Hawking explains Newtonian gravity in Chapter 2, Space and Time. The further apart the bodies are, the smaller the force. The gravitational attraction of a star is exactly one quarter that of a similar star at half the distance. This is because as we know, gravitatio...

When we draw a Newtonian free body diagram of a man standing still on land, we draw force g and the reaction force. In water when floating still, we still have force g but we also have the reaction force and buoyant force. We are not accelerating in either case. So what makes us feel weightless i...

I'd like to confirm this somewhat counterintuitive result. Starting with the definition of kinetic energy: $$E = \frac{1}{2} mv^2$$ Assume a vacuum, no external forces, and starting from rest. Adding some energy $E$ to the system by burning some fuel (by firing a rocket, etc.), the following sho...

If you send a text from your phone to your friend, do electrons move from your phone to your friend's phone? How is text transferred (physics wise)? I am a programmer and I want to know how it is working.