Model Airplane-Work-Energy Theorem and Kinetic Energy

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A model airplane flying at 22 m/s on a horizontal circle with a radius of 16m and a mass of 0.90 kg experiences a change in radius to 14m, resulting in increased speed and tension in the guidelines. The net work done on the plane can be calculated using the work-energy theorem, where the work done equals the change in kinetic energy (KE). The initial and final kinetic energies can be determined from the given parameters, leading to a final answer of approximately 5.4 x 10^2 J. The tension in the guidelines increases fourfold, which aids in calculating the new velocity and kinetic energy. The discussion concludes with confirmation that the correct answer was obtained.
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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 Alot..I got the right answer now..
 
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