KE1 vs KE2, mechanical energy change

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SUMMARY

The discussion centers on the interaction between two objects with unequal masses and kinetic energies, specifically a car with 700 Joules of kinetic energy and wind with 1400 Joules. When these two collide, the wind applies a non-conservative force that can stop the car and push it backward, utilizing the remaining kinetic energy after some energy is lost to other forms. The key equations involved include the total mechanical energy equations and work-energy principles, which illustrate how kinetic energy can be transformed into work. The conclusion emphasizes that two objects with kinetic energy can perform non-conservative work on each other as long as sufficient energy remains.

PREREQUISITES
  • Understanding of kinetic energy and its calculation (Fs=1/2m*v^2)
  • Familiarity with total mechanical energy concepts (TMEi + Wnc = TMEf)
  • Knowledge of non-conservative forces and work-energy principles (W = F*D)
  • Basic grasp of energy transformation in mechanical systems
NEXT STEPS
  • Study the principles of non-conservative forces in physics
  • Learn about energy loss mechanisms in collisions
  • Explore applications of kinetic energy in renewable energy systems, such as wind farms
  • Investigate the implications of mechanical energy conservation in real-world scenarios
USEFUL FOR

This discussion is beneficial for physics students, educators, and engineers interested in mechanics, energy transformations, and applications of kinetic energy in various systems.

normal_force
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Homework Statement


If two objects of unequal mass and unequal Kinetic energy hit each other, they lose some energy to other forms but keep enough to do Work on each other. A good example is a car and wind, a man and ball could also apply, a ball with KE could stop a running man if KE does work, though that is hard to do as energy is taken up many other forms- - back to car and wind, wind moving has mechanical energy in the form of Kinetic energy and a car has Kinetic energy, If a Car with 700 Joules of KE is moving to the right and a gust of wind with 1400 Joules from the left, what happens to the car and the wind?

Homework Equations


Fs=1/2m*v^2
TMEi+Wnc=TMEf
W=F*D
Wnc=ΔME

The Attempt at a Solution


The wind has Mechanical energy in the form of Kinetic energy, this allows the wind to apply a force, doing work by a non-conservative force as a air particles convert KE which is ME into non-conservative work, transferring energy to what it hits. The wind will be able to apply a non-conservative force, thus altering the mechanical energy of what it hits. A car with 700Joules, so TMEi-Car + (-TMEi-Wind)= TMEf

(700Joules)+(-1400Joules)=700Joules TMEf, the Car is stopped and then moved backed, the wind is doing work, the wind stopped the car and had 700 Joules left to push the car backwards.What is wind and its KE used for? Wind farms! wind with KE does work onto the blades of wind mills, the applied non-conservative force pushes the blades giving them KE which is ME, thus that ME is turned into power, electrical energy - - however, power is created which is supplied to homes and schools, thus Mechanical energy in both forms PE and KE is able to do work.
 
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I think this is quite a badly designed problem. The problem statement says..

normal_force said:
If two objects of unequal mass and unequal Kinetic energy hit each other, they lose some energy to other forms but keep enough to do Work on each other.

Sure but unless you know how much energy is lost "to other forms" you have no way to determine if the car slows a little or stops and gets blown backwards.
 
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CWatters said:
I think this is quite a badly designed problem. The problem statement says..
Sure but unless you know how much energy is lost "to other forms" you have no way to determine if the car slows a little or stops and gets blown backwards.
yep, Typo's hahahaha My badhowever, the equation is and numbers are set.
 
?
 
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CWatters said:
?

Well, okay just assume some energy is lost, and the remaining energy is 700Joules and 1400Joules to do work...
 
If the wind gust contains 1400 Joules and 700 are lost then only 700 are available to do work on the car.
 
Well, the 1400joules lost 700joules to stop the 700joule car and the remaining 700joules pushes the car back, that is the question.

It would can be said that Two objects opposite of each other with KE can do non-conservative work on each other.

The wind has finite KE and so does the car, if the energy goes to applying a non-conservative force and thus a non-conservative force the wind has superior KE, so it stops the car and then pushes it back.

Also, the car would be stopped in a short distance then pushed back
 
CWatters said:
If the wind gust contains 1400 Joules and 700 are lost then only 700 are available to do work on the car.

My previous answer is correct, it would be best to say that KE can do work even with two colliding objects as long as energy remains to do non-conservative work on the whole body, correct?
 

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