Answer:
v=32.9m/s
Explanation:
The acceleration needed to mantain a circular motion of radius r and speed v is given by the equation 
This is the centripetal acceleration. The person will feel what is called a centrifugal acceleration, of the same value, because he is not in an inertial frame (thus subject to fictitious forces, product of inertia).
We want to know the speed of his head when it is subject to 12.5 times the value of the acceleration of gravity while moving on a 8.84m radius circle, so we must do:

Hello!
A stretched spring has 5184 J of elastic potential energy and a spring constant of 16,200 N/m. What is the displacement of the spring ?
Data:



For a spring (or an elastic), the elastic potential energy is calculated by the following expression:

Where k represents the elastic constant of the spring (or elastic) and x the deformation or displacement suffered by the spring.
Solving:









Answer:
The displacement of the spring = 0.8 m
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I Hope this helps, greetings ... Dexteright02! =)
Metallic bonds! Hope this helps!! :))
Thermal energy is the answer