kinetic energy

[monty2311]

hi, does anyone know how much kinetic energy the average human uses in a day?

[beso]

Kinetic energy is the energy embodied in motion and not really the appropriate term to use in a question about energy consumption. The energy we use is actually chemical energy embodied in the bonds between atoms in the food we eat.

However both forms of energy can be measured in the same unit which in the metric SI standard is the Joule. Technically a Joule is the energy expended in moving an object a metre against a force of one newton. Practically speaking, a Joule is the amount of energy required to lift a kilogram about 100 millimetres against the force of gravity.

http://en.wikipedia.org/wiki/Food_energy
A gram of sugar holds about 10KJ (Ten thousand Joules). A gram of fat has 37 KJ. An average person will use in the order of 10MJ (Ten million Joules) of energy per day.

To answer your question. Kinetic energy in Joules is equal to half the mass of an object in kilograms times the square of its velocity in metres per second. So converting a day's food intake to kinetic energy would be the equivalent of a 100 kg person travelling at 100 metres per second. Quite a lot really.







The Joule