Man Walks Up Stairs: Work Done?

In summary, the question is asking for the work done by the man walking up the stairs, which would be calculated using the formula mgh=40*9.81*3 J. However, the answer given in the thermodynamics course tutorial is 0 J, which is surprising. For the second question, where the man walks up the stairs and then back down, the work done is also 0 J because there is no displacement. It is possible that the frame of reference used in the thermodynamics course is different from that in a physics course, where only work done on something else counts. This could explain the discrepancy in the answers. It is also worth noting that the lecturer for the thermodynamics course is a professor in that subject
  • #1
cronusmin
10
0
Q: a man(40kg) walks up the stair of 3m high, how much work done by the man?

wat i think is, the man experienced the gravitational pull, so the man should get a work done of mgh=40*9.81*3 J, is this correct?

but the answer from the thermodynamic course tutorial Q is 0 J. why?

2nd Q: a man(40kg) walks up the stair of 3m high n walk down to floor again, how much work done by the man?

for this Q, i will answer 0 J, because the displacement is 0m.
 
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  • #2
I disagree with the answer for question 1. Is that the exact question, word for word?
 
  • #3
Snazzy said:
I disagree with the answer for question 1. Is that the exact question, word for word?

the question is correct, i copy this from a thermodynamics course student. when i get the answer is 0J, i also felt surprised. how should it b 0J i think. is that the frame of reference the thermodynamics course consider is not same as physics course?
 
  • #4
Snazzy said:
I disagree with the answer for question 1. Is that the exact question, word for word?

besides tat, the lecturer for the thermodynamics course is a professor in that subject...
any idea for that?
 
  • #5
Only work done on something else counts. The man has pushed against the stairs, but those haven't moved, so he has added no energy to anything else.
 
  • #6
kamerling said:
Only work done on something else counts. The man has pushed against the stairs, but those haven't moved, so he has added no energy to anything else.

in case the Q is asking for the work done by the man, so any relation for the man pushing on the stair?
 

1. What does "work done" mean in this context?

In this context, "work done" refers to the physical effort and energy required to lift a person's body weight against the force of gravity as they walk up a flight of stairs.

2. How is work calculated in this scenario?

The work done in this scenario can be calculated by multiplying the force applied (in this case, the person's body weight) by the distance traveled (the height of the stairs).

3. Does the height of the stairs affect the amount of work done?

Yes, the height of the stairs does affect the amount of work done. The higher the stairs, the more work is required to climb them.

4. Is walking up stairs considered an efficient form of exercise?

Yes, walking up stairs is considered a very efficient form of exercise as it engages multiple muscle groups and increases heart rate, leading to improved cardiovascular health and increased muscle strength.

5. Can the amount of work done while walking up stairs be increased?

Yes, the amount of work done while walking up stairs can be increased by carrying additional weight or by walking at a faster pace, which requires more energy expenditure.

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