All Questions
7
questions
8
votes
11
answers
1k
views
Is it more work to put more (apparent) effort to get the same outcome?
I was taking my dogs for a walk yesterday evening when this question occurred to me.
The two dogs were pretty enthusiastic about the walk and wanted to run on ahead, so the leads were taut and they ...
- 257
2
votes
2
answers
178
views
Newtonian Physics vs Metabolic Equivilant (MET) calculations
I am trying to help my daughter do her physics homework. Her assignment includes calculating Calories worked off while exercising.
The formula she is using is ...
- 131
67
votes
15
answers
22k
views
Why is ascending some stairs more exhausting than descending?
I have been asked this question by school kids, colleagues and family (usually less formally):
When ascending a flight of stairs, you exchange mechanical work to attain potential Energy ($W_\text{...
- 831
18
votes
3
answers
10k
views
Which requires more energy: walking 1 km or cycling 1 km at the same speed? [closed]
I feel more tired walking 1 km than cycling 1 km at the same speed. However when cycling I am moving the extra weight of the cycle along!
- 933
1
vote
5
answers
18k
views
Lifting and putting down a weight
A man in a gym lifts a weight and then puts it down where it was before.
What can be said about the work done by the man to the weight?
Can it be equal in absolute value to the work made by the ...
- 673
0
votes
3
answers
315
views
Work power and energy
When you push your bicycle up on an inclined the potential energy of the bicycle and yourself increases. Where does this energy come from?
user60881
182
votes
14
answers
77k
views
Why does holding something up cost energy while no work is being done?
I read the definition of work as
$$W ~=~ \vec{F} \cdot \vec{d}$$
$$\text{ Work = (Force) $\cdot$ (Distance)}.$$
If a book is there on the table, no work is done as no distance is covered. If I ...
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