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My teacher explained that when an external load is applied on an object in space ,eccentric to its centre of mass, the object will be accelerated linearly(along a straight line) because there will be no resisting forces(like friction).He also added that when the same load is applied to an object lying on a suface in earth, the object rotates (because of the resisting forces) and also moves linearly.But mass resists change in state of motion.So even in space the centre of mass will be the point at which the effect of entire mass will be cocentrated.So even if there is no other resistive forces,the object should rotate.Is this right?

Qmechanic
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    Doesn't sound right. In space the object should rotate as well as move linearly. Otherwise you would not be able to use eccentric thrusters on a space ship to turn it. – Bob D Sep 02 '18 at 15:52
  • For providing rotation. A net torque should be applied on the body. A forcing acting along a line on the center of mass will not provide a torque to the object. So it will not rotate in space. I am not sure about the earth statement though. – Harshit Joshi Sep 02 '18 at 16:51
  • @HarshitJoshi But the force is applied eccentrically to the centre of mass in space. –  Sep 02 '18 at 17:11
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    @Mohan. Exactly. The object should rotate. – Bob D Sep 02 '18 at 21:21
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    Your teacher is wrong. Ask him to explain how astronauts in the ISS can do somersaults if his theory is correct. – PM 2Ring Sep 03 '18 at 05:23
  • Possible duplicates: https://physics.stackexchange.com/q/12140/2451 and links therein. – Qmechanic Sep 04 '18 at 07:34

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The law of conservation of angular momentum has to hold.

If the hit is eccentric, i.e. the force vector direction does not pass through the center of mass, an angular impulse (See this article paragraph 19.5 .) is transferred to the body, and this will result in a rotation about the center of mass, because angular momentum is conserved.

anna v
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