Mrs. Klein (59 kg) climbs a ladder to the top of the roof (3.8 m) in 18 seconds. Mr. Bruening (115 kg) completes the same task in 22 seconds and Mrs. Austin (55.5 kg) can do it in 15 seconds. Rake the teachers in order of the most powerful to the least.
power= m g h/time
can you compare them?
em..kinda
the answer doesn't need kinetic energy right?
'cause I thought since the speed is the velocity, so I kinda confusing about that
thxXD
No, just do mgh, assume no speed at top :)
To determine the ranking of the teachers based on their power, we need to calculate their power-to-weight ratios. Power is typically measured in watts and can be calculated using the formula:
Power = Work / Time
Where work is the force applied multiplied by the distance traveled:
Work = Force × Distance
In this case, since all the teachers are climbing to the same height, the work done can be calculated by multiplying their weight with the height of the roof.
Now, let's calculate the power-to-weight ratios for each teacher and rank them accordingly:
1. Mrs. Klein:
Work = Weight × Height = 59 kg × 3.8 m = 224.2 kg·m
Power = Work / Time = 224.2 kg·m / 18 s = 12.455 W
2. Mrs. Austin:
Work = Weight × Height = 55.5 kg × 3.8 m = 210.9 kg·m
Power = Work / Time = 210.9 kg·m / 15 s = 14.06 W
3. Mr. Bruening:
Work = Weight × Height = 115 kg × 3.8 m = 437 kg·m
Power = Work / Time = 437 kg·m / 22 s = 19.864 W
Based on these calculations, the ranking, from the most powerful to the least, is as follows:
1. Mr. Bruening (19.864 W)
2. Mrs. Austin (14.06 W)
3. Mrs. Klein (12.455 W)