Question

5N of force is applied to move a large nail a distance of 10 cm from an electromagnet on a frictionless table. The nail is then released. What is the best description of the change from potential to kinetic energy as the nail moves back toward the electromagnet?
A) All of the energy is kinetic as soon as the nail is released.
B) The rate of change from potential to kinetic energy is constant.
C) The rate of change from potential to kinetic energy is exponential.
D) The kinetic energy is 25 J when the nail is 5 cm from the electromagnet.

Answer 1

Answer:

C) The rate of change from potential to kinetic energy is exponential.

Explanation:

As we know that total mechanical energy must be conserved here

As we know that there is no friction force on this system of electromagnet and nail

So here we can say that that

Magnetic potential energy of the nail + electromagnet system will convert into kinetic energy of the nail as it is released.

So we will have

Initial potential energy = work done to move it away by 10 cm

$U = 5(0.10)$

$U = 0.5 J$

now as the nail is released then this potential energy will start to convert into kinetic energy

So here correct answer must be

C) The rate of change from potential to kinetic energy is exponential.