Today, we learned the definition of power and the method to calculate it.
Power is defined as the ratio of amount of work done within a time interval that it takes to do the work. Therefore, we can calculate power with this formula: P = W / Δt. The unit of power is joule / second or watt. 1 J/s = 1 w. As the formula present, power grows inversely with Δt. That means the longer someone travels, less power he or she tend to apply.
In order to calculate the power of a substance, the mass of the substance and the distance it travels have to be determined. For example, a person weights 50 kg travels upwards along stairs that is 1.8 meters long. It takes 2.4 s for the person to finish climbing the stairs. The power of that person's leg while he or she was travelling up the stair could be calculated by using the above formula:
P = W / Δt
P = ?
W = N (d) = 50 kg x 9.8 m/s^2 x 1.8 m
Δt = 2.4 s
P = (50 kg x 9.8 m/s^2 x 1.8 m) / 2.4 s
= 370 watt
This formula intrigues me as it can be used to solve real life problems when we need to know the power that a light bulb can produce within a certain amount of time or the energy it required to power up a machine. It is confusing about how the chemical energy from the body transfer into kinetic energy that moves the body. What are some processes for the chemicals that consumed in the cells convert into power that support our body? Also, why are some people able to apply more power than others do?
