Question

How is value of G determined as 6.67*10^-11_?

Answer 1

The gravitational constant appears in newtons law of universal gravitation , but it was not measured until seventy-one years after Newton's death by Henry cavendish with his cavendish experiment, performed in 1798 . Cavendish measured Gimplicitly, using a torsion balance invented by the geologist Rev. John michell. He used a horizontal torsion beam with lead balls whose inertia (in relation to the torsion constant) he could tell by timing the beam's oscillation. Their faint attraction to other balls placed alongside the beam was detectable by the deflection it caused. Cavendish's aim was not actually to measure the gravitational constant, but rather to measure Earth's density relative to water, through the precise knowledge of the gravitational interaction. In modern units, the density that Cavendish calculated implied a value for G of 6.67×10⁻¹¹ m³⋅kg⁻¹⋅s⁻²