1Anyone here watching out ????
A solid homogeneous sphere is moving on a rough horizontal surface partly rolling and partly sliding. During this kind of motion of the sphere :
A) total K.E of the sphere is conserved
B) angular momentum of the sphere about any point on the
horizontal surface is conserved
C) only rotational K.E about the C.O.M is conserved
D) none of the above
-
UP 0 DOWN 0 0 15
15 Answers
1i here also either c or d is correct. i think d is more correct .aveek please reply .and good ques.
62C is incorrect because there is a torque about the CM (due to friction)
A is incorrect because friction is acting
B is correct because there is no torque about the ground.
1sorry i mistook the option b as being all the surface,yeah b is correct
62in B dont forget that normal reactionj and MG will balance each other;s torque.q
62Torque can be zero even when force is not
that is because it acts along the plane..
1Nishant Sir...which is taking place first...skidding or rolling ??? As far as i think it should be skidding
62partly rolling means skidding :D
what do you mean by which will take place first?
It is given that it is partly rolling (aka skidding :P)
1nishant sir can you please tell me what is the inst. center of rotation of a body if it isn't rotating at all ?also suppose that a body is performing rotational as well as circular motion. at one instant it increases its ang. vel. keeping ang. moment. conserved.what will the concequences be?
1@Nishant Sir : If it's so, then there is an ext torque ,i.e friction acting between the sphere and the horizontal surface....so how can we conserve angular momentum about it ???
62forque is r x f
not f
radius vector is in the same line as the frictional force..
so at any point along the force, we can conserve the angular momentum.
1
AT the horizontal surface the frictional force is acting tangentially to the surface against the motion whereas the torque at that point is directed along the motion tangentially so net ext. torque is zero.