How Long to Climb Three Flights of Stairs?

AI Thread Summary
To determine the time taken to climb three flights of stairs (9.7m), a person weighing 150lbs (667.5N) calculates the work done against gravity as 6474.75J. The average power expended is derived from the work and the time taken, which was estimated at 21.33 seconds. This results in a power output of 248 watts or 0.332 horsepower. The calculations and results are deemed reasonable for the scenario presented. The discussion emphasizes the importance of estimating time for accurate power calculations.
luvlybug1025
Messages
4
Reaction score
0

Homework Statement



Determine the time it takes to climb three flights of stairs (height = 9.7m). Compute the work done against gravity. Compute the average power expended in watts and in horsepower.

Person = 150lbs.

Homework Equations



h = 9.7m
4.45N/1lb
Avg Power = change in W/change in t
1hp = 746W
F=ma
W = F * d

The Attempt at a Solution



Ok...so, my 150lb=667.5N. That's my F now.
W = f * d = 667.5N * 9.7m = 6474.75J
Once I can find the time it took, then I can use that and the work to find the average power. I just can't figure out how to get time traveled from Work done. Am I on the right track?
 
Physics news on Phys.org
You are on the right track. Since the time is not given, you have to come up with a reasonable estimate or climb three flights of stairs and time yourself.
 
Wow, that makes sense. (I had to measure the stairs myself to.)
Thanks very much for replying so quickly!
I got 21.33s
Work = 5303.8J
Power = 248Watts = 0.332hp
That seems reasonable, right?
 
Pretty reasonable.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Finding work of a man running up stairs
Replies
6
Views
5K
Work done by a person climbing stairs
Replies
2
Views
5K
How Does Climbing Stairs Compare to Lighting a Bulb in Energy Use?
Replies
9
Views
7K
How Much Work Is Involved in Climbing Stairs for a 60kg Person?
Replies
12
Views
23K
Calculating Work for Climbing Stairs
Replies
1
Views
5K
Calculating Power of a person running up stairs
Replies
1
Views
2K
What Is the Average Power of Bullets Bouncing Off Superman?
Replies
26
Views
3K
Work Done: Comparing Elevator & Staircase Climbs
Replies
2
Views
2K
Work done climbing a flight of stairs.
Replies
6
Views
13K
Calculating Time to Consume Energy from Running Up Stairs
Replies
1
Views
3K

Hot Threads

Recent Insights

Back
Top