A man (90 kg) climbs up a ladder 30 meters high. The energy he has due to his
position can be calculated.
| = mass of the man |
| = acceleration due to gravity |
| = position of man after climbing the ladder |
| Joules = unit for work or energy |
Energy can be converted to heat or calories.
1 calory is the amount of heat needed to raise 1 gram of water by .
The calories in food are kilocalories or thousand calories.
When the man's potential energy is converted to calories, it becomes :
Suppose the man ate a packet of chips which is about 2000 Calories. (Notice the capital
c for Calories. If calories is written with a capital c, then it is equal to kilocalories.)
He would have to climb up and down 30 meter high ladder about 150 times to get rid of
what he ate.
Of course this figure is disregarding the energy needed to maintain
himself.