Power Stairs Problem: 690 W Needed for 44 kg Person to Climb 12 Flights in 15s

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Homework Help Overview

The problem involves calculating the power required for a 44 kg person to climb 12 flights of stairs, each with a height of 2 meters, within a time frame of 15 seconds. The relevant equation for power is given as P=W/T.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the calculation of total distance by multiplying the number of flights by the height of each flight. There is uncertainty about the correct interpretation of time in the power equation. Questions arise regarding the definitions of initial and final potential energy and the calculation of work.

Discussion Status

Some participants have provided guidance on the relationship between work and force, noting that work can be calculated as force multiplied by displacement. The displacement has been identified as 24 meters, and there is a discussion about converting mass to weight in Newtons. There is acknowledgment of multiple approaches to the problem.

Contextual Notes

Participants express confusion about the definitions of work and weight, and there is a mention of a teacher's provided answer of 690 W, which may influence the discussion. The original poster indicates feeling lost and seeks clarification on the steps involved.

sweedeljoseph

Homework Statement


How much power is needed for a 44 kg person to climb 12 flights of stairs that each have a height of 2 meters, in a time of 15 seconds?

Homework Equations


P=W/T

The Attempt at a Solution


answer from the teacher is 690 W. i remember doing the something like this in class but i don't remember exactly what all to do. wouldn't you multiply 12 by 2 so its total distance then multiply it by the 15 for the total time? or is that just time in general, the total? then put it into the power equation? i know youre supposed to convert the mass into N but that's it. I am so lost please help me.

thank you!
sweedeljoseph
 
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sweedeljoseph said:

Homework Statement


How much power is needed for a 44 kg person to climb 12 flights of stairs that each have a height of 2 meters, in a time of 15 seconds?


Homework Equations


P=W/T


The Attempt at a Solution


answer from the teacher is 690 W. i remember doing the something like this in class but i don't remember exactly what all to do. wouldn't you multiply 12 by 2 so its total distance then multiply it by the 15 for the total time? or is that just time in general, the total? then put it into the power equation? i know youre supposed to convert the mass into N but that's it. I am so lost please help me.

thank you!
sweedeljoseph

U_0+W=U_f\rightarrow W=\Delta U. Then, use your relevant equation to solve.
 
whats U initial? or U final?
 
sweedeljoseph, there is probably more than one way to solve this. You have the key equation P=W/t

Yes, t is the TOTAL time

Now you just need to find the Work. Work is defined as Force*displacement

You found the displacement to be 24 meters.

What is the force in this case?

Casey
 
well force is in N and you can make the mass into Newtons. mass is 44 kg so times 9.8 its 431.2 N. so I am guessing that's the force?

i just put it in the calculator. it works! thank you. for some reason i kept thinking W was weight instead of work. i feel stupid haha.

thank you!
sweedeljoseph
 

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