In numerous formulas from school and university physics courses, the letter "g" is often found. What does she mean?
This letter stands for the so-called "acceleration of free fall". It is with this acceleration that all bodies fall to the surface of the Earth: from a light feather to a heavy piece of lead. And if it were not for air resistance, then they would fall at the same speed and, accordingly, would land at the same time.
On Earth, the acceleration due to gravity is approximately 9.8 m/s², to be exact 9.80665 m/s². This is the average value for the planet, obtained when measuring at a latitude of 45.5 °. And, for example, on the Moon g=1.62 m/s². Remember how easily the first astronauts jumped on its surface. And on the giant Jupiter g = 23.95 m / s², i.e. almost 2.5 times more than on Earth.
Also, the letter "g" denotes overloads in vehicles, aviation and astronautics, when a person’s weight increases significantly. For example, when we just stand still, we experience an overload of 1g. But since this is a common occurrence on Earth, we, of course, do not notice such an "overload". If we are on board a plane taking off, then we experience an overload of 1.5g, i.e. our weight increases by 1.5 times. A skydiver, when his parachute opens and the speed instantly decreases from 60 m/s to 5 m/s, experiences an overload of 5g. Trained pilots can withstand g-forces up to 9g. There is also an absolute record holder for overloads. Formula 1 driver Kenny Braque, having an accident on his car, experienced an overload of 214g and survived!
The letter "g" has an older sister – G. The letter G in physics denotes a fundamental physical quantity – the gravitational constant or Newton’s constant. However, to be honest, this quantity was not explicitly present in Newton’s works. And for the first time it appeared in the XIX century in the works of another famous physicist – Poisson. But since G is used precisely in Newton’s law of universal gravitation, this quantity was named after his last name.
There’s so much fun going on with that little "g"!