Heat and work -- how much energy to climb the rope....

In summary, the question asks how much energy is dissipated as heat in a single climb when a standard man with a mass of 70 kg climbs 15 m up a vertical rope, using 23% of the total energy required for the work. The equation Q = mgΔh can be used to solve this problem, with the unknown energy expended by the man. The interpretation of the statement "23% of the total energy required is used to do the work" is that 23% of the energy expended by the man goes into the useful work of ascending the rope.
  • #1
Sam Vermeulen
5
0

Homework Statement


A standard man climbs 15 m up a vertical rope. How much energy (in cal) is dissipated as heat in a single climb if 23% of the total energy required is used to do the work? (Assume the standard man has a mass of 70 kg.)

Homework Equations


Q = mgΔh

The Attempt at a Solution


I used Q = mgΔh and took 23% of that and then converted it to calories and it was not correct. I think I am just not understanding what the question is asking for.
 
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  • #2
Sam Vermeulen said:
if 23% of the total energy required is used to do the work?
That part doesn't make any sense. Is it copied word-for-word? Are you sure it's not 123%? How could it take less work than the change in energy?
 
  • #3
berkeman said:
That part doesn't make any sense. Is it copied word-for-word? Are you sure it's not 123%? How could it take less work than the change in energy?
The wording is unclear, but I would it interpret as 23% of the energy the man expends goes into the useful work of ascending the rope.
 
  • #4
Ah, that would make a lot more sense! Thanks haruspex.
 
  • #5
berkeman said:
That part doesn't make any sense. Is it copied word-for-word? Are you sure it's not 123%? How could it take less work than the change in energy?
Yeah copied it word for word I'll try what haruspex said. Thank you for the help.
 
  • #6
haruspex said:
The wording is unclear, but I would it interpret as 23% of the energy the man expends goes into the useful work of ascending the rope.
How would I go about this without knowing the amount of energy the man expended in the first place?
 
  • #7
Sam Vermeulen said:
How would I go about this without knowing the amount of energy the man expended in the first place?
Just create an unknown for that and see what equation you can write.
 

Related to Heat and work -- how much energy to climb the rope....

1. How is heat related to energy?

Heat is a form of energy that is transferred between objects or systems due to a temperature difference. It is the flow of thermal energy from a warmer object to a cooler object.

2. What is work in terms of physics?

In physics, work is defined as the application of a force over a distance. It is measured in joules and is used to describe the transfer of energy from one object to another.

3. How is heat and work related?

Heat and work are both forms of energy transfer. While heat is the transfer of thermal energy, work is the transfer of mechanical energy. Heat can be converted into work, and work can be converted into heat.

4. What is the relationship between energy and climbing a rope?

The amount of energy required to climb a rope is directly related to the height and mass of the climber. As the climber lifts their body mass against the force of gravity, work is being done and energy is being expended.

5. How does friction affect the amount of energy required to climb a rope?

Friction is a force that resists motion between two surfaces. When climbing a rope, friction between the rope and the climber's hands or feet can make the task more difficult and require more energy to overcome. This energy is eventually converted into heat due to the friction between the surfaces.

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