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This question comes from working with rigid rolling disks and wheels. For example, when a rotating disk comes in contact with a non-rotating disk, the non-rotating disk will start to rotate due to friction creating a torque on the body.

So if we just look at two rigid bodies, and forget about air resistance and other forces acting on the system of two bodies, is it in the theoretical case possible to transfer some or all of the kinetic energy of body 1 to body 2 without losing energy, in the form of friction, sound and heat, in the process? Does it make a difference in the result, if the kinetic energy of body 1 is pure rotational energy or translational energy or a combination of both?

To be clear, body 2 should have gained some or all of body 1's kinetic energy while the total kinetic energy of (body 1 + body 2) is the same.

sammy gerbil
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SwedeGustaf
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The conservation of kinetic energy occurs only in a perfectly elastic collision where coefficient of restitution is equal to one. Hence, yes, in an ideal situation, where no energy is lost through heat and sound upon collision and contact, it is possible. However, in reality, a perfectly elastic collision is never possible, so conservation of kinetic energy is not possible.

Manas Singh
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QuIcKmAtHs
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At the macroscopic level some kinetic energy will be converted to some other form (heat, sound, etc.) making such collisions inelastic. At the microscopic level some collisions (e.g., those involving ideal gases molecules) approach being perfectly elastic. I believe there are some other examples at the microscopic level.

Bob D
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Yes. For example Newton's cradle. Same weight of the spheres, all kinetic energy is transferred to the sphere at rest.