Conservation of energy equation

In summary, the conversation discusses the task of writing a conservation of energy problem that produces a given equation. The equation involves a 3kg object on a planet with 15% of Earth's gravity, running at 7m/s and placed on a 2.0m hill. The questioner wonders about the meaning of the "T" term in the equation and speculates that it could represent tension. They then propose a problem involving a 3kg rabbit bungee jumping on the same planet and calculate the jumping height needed for the rope to become taut at 7m/s. They ask for feedback on whether this problem makes sense in terms of energy conservation.
  • #1
zoner7
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0

Homework Statement


My professor has provided me with an equation, and my task is to write a conservation of energy problem whose solution would produce said equation.

Here is the equation:
(1/2)(3kg)(7m/s)^2 + 0 + (0.15)(3kg)(9.8m/s^2)(2.0m) = 0 + 0 + T(2.0m)


Homework Equations


Work internal = 0
W = F . d


The Attempt at a Solution



A 3 kilogram rabbit who lives on a planet with 15% the gravity of that of earth. During his daily run, while on top of a 2.0m hill, his speed peaks at 7m/s. At this point, what is his total energy?

This question accounts for the first two terms of the equation, both of the left side. I am still left wondering, however, what the T on the right side stands for. Note that this is a thermodynamics class; however, we have had less than an hour of class and have yet to learn any thermodynamics. Could T stand for temperature here? If so, how can I use this value in terms of energy?
 
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  • #2
Temperature times length does not have the proper units (of course, all the terms should have units of energy, i.e. Joules).
Force times length, however, does. One word that comes to mind is tension... ?
 
  • #3
ah hah.

Suppose my problem looks like this, then:

A 3 kilogram rabbit named Joe lives on a planet with 15% the gravity of that of earth. Joe loves to bungie jump. During one of his more adventurous endeavors, Joe ties a rope to himself and a bridge, leaving exactly 2m worth of slack. Joe calculates his initial jumping height such that the rope will become taught when he reaches 7m/s; his calculations report that he will be 2m above the ground at this time. Write a conversation of energy equation describing the rabbit's energy when the rope becomes taught.

Does this make sense? The tension on the rope is acting external to the system of the rabbit. Since the rabbit is 2m above the ground, and since gravitational potential energy is mgh, that should check out as well. What do you guys think?
 

1. What is the conservation of energy equation?

The conservation of energy equation is a fundamental principle in physics that states that energy cannot be created or destroyed, only converted from one form to another. It is represented by the equation E = mgh, where E is energy, m is mass, g is gravitational acceleration, and h is height.

2. How is the conservation of energy equation applied?

The conservation of energy equation is applied in various scientific fields, including mechanics, thermodynamics, and electromagnetism. It is used to analyze the flow and transformation of energy in a system and to make predictions about the behavior of physical systems.

3. What are the assumptions behind the conservation of energy equation?

The conservation of energy equation is based on the assumption that the system being studied is isolated, meaning that there are no external forces acting on it. It also assumes that there is no energy loss due to friction or other dissipative forces.

4. Can the conservation of energy equation be violated?

No, the conservation of energy equation is a fundamental law of nature and has been validated by numerous experiments. However, in certain situations, it may appear to be violated due to incomplete understanding of all the energy transfers and conversions involved.

5. What are some real-life applications of the conservation of energy equation?

The conservation of energy equation has many practical applications, such as in the design of energy-efficient buildings, the analysis of energy usage in industries, and the development of renewable energy sources. It is also used in the study of celestial mechanics and the behavior of particles at the atomic level.

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