Excuse me, the mobile phone received a short message. Is it light or heavy?

It is light from the point of view of mechanics and inertia.

Because under normal circumstances, when we receive a text message, we will habitually take out our mobile phone and raise it by 30 to 50 centimeters, that is, 30 to 50 centimeters from the ground. According to gravity, it is the interaction between objects due to mass. Its size is related to the mass of the object and the distance between two objects. The greater the mass of objects, the greater the attraction between them; The farther away objects are, the less attractive they are.

The gravitational force between two objects that can be regarded as particles can be calculated by the following formula: f = GMM/R 2, that is, the gravitational force is equal to the product of the gravitational constant multiplied by the mass of two objects divided by the square of their distance. Where g represents the gravitational constant, and its value is about 6.67× 1 1 power unit n m2/kg2. It was measured by British scientist cavendish through the torsion balance experiment.

Now you lift the phone, that is, the R becomes larger and the distance becomes larger, then the gravity will become smaller, and then the gravity of the phone will become lighter.