Gravitational Force of an object

AI Thread Summary
Sir Isaac Newton developed the law of universal gravitation, which describes the gravitational force between two masses but did not determine the exact value of the gravitational constant 'G'. The measurement of 'G' is credited to Henry Cavendish through his famous experiment. This gravitational constant can indeed be applied to calculate the gravitational force of smaller objects, such as a bottle or a human body, although the forces would be significantly smaller. Understanding these concepts enhances knowledge of gravitational interactions in everyday life. Learning about these principles can be rewarding and insightful.
ElectroViruz
Messages
22
Reaction score
1
Just a little curious. What formula did Sir Isaac Newton used to find out the exact value of Earth's gravitational force ? Can we apply that formula to find out the gravitational force of other objects ? Let's say, calculating the gravitational force that my bottle has or our body. I know that the value in such objects with small mass would be minute, but I thought it'd be cool to know :)
 
Physics news on Phys.org
Thread 'Gauss' law seems to imply instantaneous electric field propagation'
Imagine a charged sphere at the origin connected through an open switch to a vertical grounded wire. We wish to find an expression for the horizontal component of the electric field at a distance ##\mathbf{r}## from the sphere as it discharges. By using the Lorenz gauge condition: $$\nabla \cdot \mathbf{A} + \frac{1}{c^2}\frac{\partial \phi}{\partial t}=0\tag{1}$$ we find the following retarded solutions to the Maxwell equations If we assume that...
Maxwell’s equations imply the following wave equation for the electric field $$\nabla^2\mathbf{E}-\frac{1}{c^2}\frac{\partial^2\mathbf{E}}{\partial t^2} = \frac{1}{\varepsilon_0}\nabla\rho+\mu_0\frac{\partial\mathbf J}{\partial t}.\tag{1}$$ I wonder if eqn.##(1)## can be split into the following transverse part $$\nabla^2\mathbf{E}_T-\frac{1}{c^2}\frac{\partial^2\mathbf{E}_T}{\partial t^2} = \mu_0\frac{\partial\mathbf{J}_T}{\partial t}\tag{2}$$ and longitudinal part...
Thread 'Recovering Hamilton's Equations from Poisson brackets'
The issue : Let me start by copying and pasting the relevant passage from the text, thanks to modern day methods of computing. The trouble is, in equation (4.79), it completely ignores the partial derivative of ##q_i## with respect to time, i.e. it puts ##\partial q_i/\partial t=0##. But ##q_i## is a dynamical variable of ##t##, or ##q_i(t)##. In the derivation of Hamilton's equations from the Hamiltonian, viz. ##H = p_i \dot q_i-L##, nowhere did we assume that ##\partial q_i/\partial...
Back
Top