Model Airplane-Work-Energy Theorem and Kinetic Energy

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SUMMARY

The discussion centers on calculating the net work done on a model airplane transitioning from a circular path of radius 16m to 14m while experiencing an increase in speed and tension in the guidelines. The initial kinetic energy (KE) is calculated using the formula KE = 1/2(mv^2), where the mass is 0.90 kg and the initial speed is 22 m/s. Participants confirmed that the final kinetic energy is approximately 5.4 x 10^2 J, with some minor discrepancies due to rounding. The key takeaway is that understanding centripetal force and its relationship to tension is crucial for solving such problems.

PREREQUISITES
  • Understanding of kinetic energy calculations using KE = 1/2(mv^2)
  • Knowledge of centripetal force and its relation to tension in circular motion
  • Familiarity with the concepts of work and energy in physics
  • Basic algebra skills for manipulating equations and solving for unknowns
NEXT STEPS
  • Explore advanced applications of the Work-Energy Theorem in circular motion
  • Learn about the effects of changing radius on centripetal force and velocity
  • Study the principles of tension in different physical contexts
  • Investigate real-world applications of kinetic energy in aerodynamics
USEFUL FOR

Students and educators in physics, particularly those focusing on mechanics, as well as hobbyists interested in model airplane dynamics and energy calculations.

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1. A model airplane is flying at a speed of 22 m/s on a horizontal circle of radius 16m. The mass of the plane is 0.90 kg. The person holding the guidelines pulls it in until the radius of the circle becomes 14m. The plane speeds up, and the tension in the guideline becomes four times greater. What is the net work done on the plane



2. KE=1/2(mv^2),
W=KE final-KE initial



3. Obviously the radius and tension is throwing me off in the problem. I know how to find the KE.. I know the answer is suppose to be 5.4*10^2J.. Can someone lead me in the right direction or help with this problem
 
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You can find both the initial kinetic energy and Centripetal force from what's given.

Then, you know the Centripetal (tension) force will become four times as great. That should help you calculate the new velocity, and therefore you can calculate the new kinetic energy.

The answer I got was 5.5 * 10^2 J but I might have just had rounding issues. Hope that helps!
 
Mattowander said:
You can find both the initial kinetic energy and Centripetal force from what's given.

Then, you know the Centripetal (tension) force will become four times as great. That should help you calculate the new velocity, and therefore you can calculate the new kinetic energy.

The answer I got was 5.5 * 10^2 J but I might have just had rounding issues. Hope that helps!


Thanks a lot..I got the right answer now..
 

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