HOW MUCH POWER DO YOU HAVE IN YOUR LEGS? The speed with which work is performed is called power. This is calculated as work per unit of time. The less time it takes to do the same amount of work, the more power is produced. Objective: Calculate the work that you do when you climb a flight of stairs. Procedure: 1. Convert your weight from pounds to kilograms and then from kilograms to Newtons. (You may use your actual weight if you know it, or you may invent a weight to use.) Record these values in the data table on the next page. 2. Find a set of stairs. Use only the vertical portion-if your stairs have a switchback, just walk on the lower or upper portion of the stair. (Since you might not have a metric ruler at your house, I will provide the height of an average stair in centimeters.) 3. Convert the average height of a stair from centimeters to meters. 4. Determine the total vertical distance of your climb using the equation provided. 5. Walk or run up the stairs for 3 trials, time each trial. 6. Determine the average time to climb the stairs. 7. Use the Calculation areas below to determine the Work and Power of your legs during the climb up the stairs. B. Work is measured in Joules (J) and Power is measured in Watts (W). 9. Just for fun: Convert your power into Horsepower. The conversion is on the calculations page. Conversion setup for weight (in pounds) to mass (kg) to weight in Newtons.Conversion setup for weight (in pounds) to mass (kg) to weight in Newtons. Change your weight (in pounds) to mass (in kg) Change your mass (in kg) to weight (in Newtons) Your weight in pounds 1 kg Your mass: 2.2 pounds F(w) = mgData Table Enter your data into the table below: Runner's weight (Ibs.) Runner's mass (kg) Weight in Newtons (N) Height of one step (cm) 18 Height of one step in meters (m) (1m = 100cm) Number steps in flight Vertical distance traveled (m) (Height of 1 step in meter * # of steps) Trial 1 Trial 2 Trial 3 |Average Time Time (s) Average time = (Trial 1 + Trial 2 + Trial 3) divided by 3 Work (J) Power (W) Horsepower (hp)Calculations 1. To find your mass: 2. Average time = average time = [time +time +time) 3 3. Calculate the work done for climbing the flight of stairs. W = Fd 4. Calculate the power of your legs using the following formula: P = W 5. The unit for power in the English system is the horsepower. Calculate you horsepower for climbing the flight of steps Your power in watts Watts 740 Maraspower