How to Calculate Power Output

Step-by-Step Guide

1. 1

   Step 1: Calculate work.

   In mechanical physics, work is the amount of force needed to move something over a selected distance.
   
   The formula for work is:
   Work=Force∗Distance{\displaystyle {\text{Work}}={\text{Force}}*{\text{Distance}}} To understand this concept, think about a 100 pound cement block.
   
   Moving that block 2 feet requires twice as much work as moving the same block 1 foot.
   
   This is also the same amount of work required to move a 200 pound block for a distance of 6 inches (1/2 a foot).
2. 2

   Step 2: Define mechanical power.

   Power is the rate at which work is performed over time.
   
   The basic formula for defining power is:
   Power=WorkTime{\displaystyle {\text{Power}}={\frac {\text{Work}}{\text{Time}}}} Think again about the 100 pound cement block.
   
   Moving that block 2 feet in 10 seconds requires twice as much power as moving the same block for the same distance in 20 seconds.
   
   Moving the same object faster requires more power. , You need to determine whether you are measuring work and power in traditional English units or in metric units.
   
   The English unit for work is the “foot-pound.” This comes from multiplying the distance measured in feet by the force measured in pounds.
   
   The unit for power comes from dividing by time, in seconds.
   
   The power unit is the “foot-pound per second.” A more familiar term is the “horsepower,” which is defined as 550 foot-pounds per second.1 Horsepower=550foot-poundssec.{\displaystyle 1{\text{ Horsepower}}=550{\frac {\text{foot-pounds}}{\text{sec.}}}} The metric unit for work is a joule.
   
   A joule is equal to one Newton-meter, which is the amount of work needed to move a 1 Newton force a distance of 1 meter.
   
   When you divide work by time, you get power, measured in units of joules per second.
   
   This is also called a Watt.1 Watt=1 Joule Sec.=1 Newton-Meter Sec.{\displaystyle 1{\text{ Watt}}=1{\frac {\text{ Joule}}{\text{ Sec.}}}=1{\frac {\text{ Newton-Meter}}{\text{ Sec.}}}} , Whether you are solving a physics problem in class or are actually calculating power from a real-world application, you need to collect certain information first.
   
   You can learn the information that you need by reviewing the measurement units.
   
   For example, suppose you want to calculate in the following problem:
   A student doing chin-ups lifts his 150 lb. body a distance of
   1.5 feet in 2 seconds.
   
   How much power is the student exerting? Force=150 lbs.{\displaystyle {\text{Force}}=150{\text{ lbs.}}} Distance=1.5 feet{\displaystyle {\text{Distance}}=1.5{\text{ feet}}} Time=2 sec.{\displaystyle {\text{Time}}=2{\text{ sec.}}} , Whether in the metric system or the English system, once you have collected the data for the force, the distance and the time, apply them to the formula to find the mechanical power.
   
   Power=Force∗DistanceTime{\displaystyle {\text{Power}}={\frac {{\text{Force}}*{\text{Distance}}}{\text{Time}}}} Power=150lb.∗1.5feet2sec.{\displaystyle {\text{Power}}={\frac {150{\text{lb.}}*1.5{\text{feet}}}{2{\text{sec.}}}}} Power=225ft-lb2sec.{\displaystyle {\text{Power}}={\frac {225{\text{ft-lb}}}{2{\text{sec.}}}}} Power=112.5ft-lbsec.{\displaystyle {\text{Power}}=112.5{\frac {\text{ft-lb}}{\text{sec.}}}} Since 1 horsepower equals 550 ft-lb/sec., this is about equal to one-fifth of a horsepower.
3. 3

   Step 3: Determine the units you're using for work and power.

4. 4

   Step 4: Collect the available data.

5. 5

   Step 5: Multiply force by distance and divide by time.

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