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Is it only because of the less friction involved or at there other reasons?

Danu
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N.S.JOHN
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  • If you "rolled" a box you would need to raise its centre of mass but you would do this so as not to do work against the frictional forces. – Farcher Feb 22 '16 at 08:09
  • @farcher i didnt mean rolling a box only pushing it. – N.S.JOHN Feb 22 '16 at 08:22
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    I did understand that from you question. I mentioned the rolling to indicate that the answer to you question is the answer that you have given - the force of friction which in the case of rolling does little or no work as compared with the work done against friction in the case of a box. Surface irregularities would make it harder to move a box whereas a sphere would roll over them. – Farcher Feb 22 '16 at 08:27
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    Related : http://physics.stackexchange.com/q/149409/ – biryani Feb 22 '16 at 08:38

3 Answers3

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if you are trying to move the bodies rather than roll them you wouldn't find one moving the sphere easier than moving the block as there would be no rolling friction,the only kind of friction acting would be sliding friction which would be same for both the bodies

Anirudh PVS
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  • Practically a box would tent to "dig in" while slid along, whereas a sphere can just glide over whatever asperities. – John Alexiou Feb 22 '16 at 17:36
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Movements under gravitational acceleration requires shifting of center of the mass. Any object stays at rest on the horizontal plane will have it's center of mass within the walls of its footprint.

A cube will lose this stability only when one of its side is lifted above 45degree angle. Only above that angle the center of mass of the cube will go outside of its footprint, thus fall on its side.

But for a sphere, its footprint is a tiny point on the horizontal plane. Thus any slight push on it's side will shift the center of the mass outside of the footprint and makes it to roll.

soosai steven
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Its because the rolling friction will act to make point of contact velocity=0 If pt of contact v=0 Then rolling friction cease to act Then it can roll for longer time witout effort

Engineer
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