Can a Ball Roll Purely Without Friction?

AI Thread Summary
A rigid ball cannot roll purely without friction while maintaining constant velocity on a rigid surface, as friction is necessary for the tangential force that enables rolling. Without friction, the ball would either slide or spin in place, lacking the necessary interaction to achieve both horizontal movement and rotation. The inertia of the ball would require an external force to initiate motion, as the two motions of spinning and horizontal velocity would remain independent in a frictionless scenario. The discussion also suggests that while theoretical conditions could be imagined, they do not apply to our physical universe. Therefore, friction is essential for true rolling motion.
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suppose a rigid ball have pure rolling with constant velocity on rigid level without friction , is it possible ?
 
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What causes the 'rolling'? Isn't it the inertia of the mass countered by a tangential force at the bottom caused by friction? Otherwise it would be sliding.
 
If you ignored friction just between the surfaces (otherwise getting it rolling in the first place would be difficult), you could get the ball to "spin" but it would do so in place. If you wanted it to move as well you'd have to push it. The two motions (spin and horizontal velocity) would be independent (I don't think the spin would have any reactionary influence on the velocity without friction, but I'm not certain).

Anything is possible if you design a funky universe around desired conditions.
 

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