Power

Discussion

Intro

P = ΔW
Δt
P = dW
dt
   
P = Fv cos θ P = F · v
power (W) device, phenomena, process, event
  gamma ray burster
3.6 × 1039 typical quasar
3.6 × 1026 the sun
1.25 × 1015 most powerful laser (Petawatt)
1.3 × 1013 total human consumption, global
3.2 × 1012 total human consumption, US
1.2 × 1010 space shuttle at launch
109 ~ 1010 large commercial power plant
4,700,000 most powerful locomotive (GE AC6000 CW)
783,000 most powerful truck (Terex TR100)
468,000 most powerful car (McLaren F1)
10,000 Watt's steam engine of 1778
746 1 horsepower
100 human, daily average
0.293 1 btu/h
10−5 human, sounds produced during normal speech
Power of Some Things

The kilowatt-hour is a unit of energy used by electrical utilities.

The Btu per hour (often erroneously shortened to Btu) is a unit of power used by the heating, ventilation, and cooling industry (HVAC).

A horsepower is a unit of power sufficient to raise 33,000 pounds 1 foot every 1 minute (550 lbs, 1 ft, 1 sec) equivalent to roughly 745.70 W

physiology

power(W) activity
800 playing basketball
700 cycling (21 km/h)
685 climbing stairs (116 steps/min)
545 skating (15 km/h)
475 swimming (1.6 km/h)
440 playing tennis
400 cycling (15 km/h)
265 walking (5 km/h)
210 sitting with attention focused
125 standing at rest
120 sitting at rest
83 sleeping
Power of various human activities Source: Physics of the Body
organ
mass
(kg)
power
(W)
power density
(W/kg)
% of total
liver & spleen 23 27
brain 1.40 16 11 19
skeletal muscles 28.00 15 0.55 18
kidneys 0.30 9.1 30 10
heart 0.32 5.6 17 7
remainder 16 19
total 65 85 100
Power of various human organs Source: Physics of the Body