A vertical distance of 2.4m separates the floors in a house. A student weighing 44 kg climbs the stairs to the second floor. Find the average power (in watts) necessay to accomplish this if the stairs are climbed in (a) 10 sec and (b) 2 sec.
2007-01-22 14:42:35 · 5 answers · asked by virginiawahoo13 1 in Science & Mathematics ➔ Physics
Power = force x distance / unit of time
Mass x g = force
distance 2.4 meters
Time 2 sec
You'll have to look up the conversion to Watts I don't have that handly
kg x (meters/ sec^2) x meters / sec = Nm/sec
2007-01-22 14:50:11 · answer #1 · answered by Roadkill 6 · 0⤊ 0⤋
Since Power = Work / Time you need to first find out how much Work it takes for a 44 kg student to climb the stairs. This comes out to be 44kg * 9.8m/s2 * 2.4m = 1034.88 Nm. If you divide that by a time of 10 sec you get a power rating of 103.488 Watts, if 2 sec, you get 517.44 Watts. Check the link for more info.
2007-01-22 15:03:54 · answer #2 · answered by Andrea P 1 · 0⤊ 0⤋
A Joule is a kg*m^2/s^2
Watts are Joules / s
G = 9.8 m / s^2
44kg * 2.4 m * 9.8 m / s^2 = 1034.88 Joules
To figure out the watts:
a: just divide by 10 seconds. 103.488 Watts
b: just divide by 2 seconds. 517.44 Watts
2007-01-22 14:53:09 · answer #3 · answered by professional student 4 · 0⤊ 0⤋
Power = Work / Time
= (Force * Distance) / Time
= ((Mass * Gravity) * Distance) / Time
So... (44 * 9.81 * 2.4) / t
a) 103.594 watts
b) 517.968 watts
2007-01-22 14:54:10 · answer #4 · answered by Procerus 2 · 0⤊ 0⤋
man, if your that smart you should be using your time to take over the world.
2007-01-22 14:47:00 · answer #5 · answered by lewismcneillis 1 · 0⤊ 0⤋