VIDEO: Examples of indolence

Indolence - what is it?

Already Galileo recognized the principle of inertial mass and today's principle school books put it something like this: All bodies are sluggish. But what does that mean?

• Bodies maintain a state of motion (curiously, this also includes the state of rest) when no external force acts on them.
• This behavior, called indolence, is a property of a body. How inert a body is is indicated by the physical quantity "mass". What physicists call "mass" is called "weight" in everyday life and is given in kilograms.
• If you want to get a body in motion, you need an external force. This force must of course be greater, the more inert a body is, i.e. the more mass it has.

Examples from everyday life - this is how indolence becomes noticeable

Examples from everyday life in which laziness or the inert mass of bodies plays a role, there are of course innumerable. In the following, therefore, examples are given that reveal or reveal little obvious things such as friction. lead to accidents. And you can understand these examples with your own small experiments - only materials from the household are required for this.

• In order to change the state of motion of a body, a force is required. However, one often has the impression that objects change their movement "almost by themselves", that is, without any external influence. For example, a car quickly comes to a standstill when it is no longer being driven. In this case, however, the acting force, namely friction, is "hidden". Galileo already recognized this fact.
• Humans (as a mass) are also inert, here natural in the physical sense, and retain their original state of motion. If a car brakes suddenly, the occupants fly on almost unchecked - into the windshield. This can also happen to standing passengers in buses and trains. Belts ensure safety in the car or Holding on to public transport. As an experiment on your own, you can load a small block of wood onto a cart and let it hit the wall at a certain speed. Now attach the block to the cart with a rubber band.
• Even bends are tough: the vehicle occupants are sluggish and actually want to maintain the state of motion "straight ahead". In curves, this leads to the familiar centrifugal forces. Simulate cornering by letting the cart loaded with the block drive through rapid curves and watch where the sluggish block flies.
• To try out: the heavier the mass, the more sluggish it is. Place a styrofoam block and a heavy weight of a beam balance on top of it on a sheet of paper. The sheet of paper should hang slightly over the edge of the table. Now pull the sheet of paper away quickly with one jerk. The weighing piece falls - large inertial mass - onto the table top. The styrofoam block - a small inert mass - falls to the floor next to the table. Try the same experiment with 10 cent pieces stacked on top of each other. What number do you need so that you can quickly pull away a postcard underneath without the stack tipping over?