rotational
A disc of mass m radius r is given a velocity v and angular velocity w and released on a horizontal surface with coeff of friction u. It is given that v=rw/4 and w is opposite to v then find time at which pure rolling starts.
I@Gyro Gearloose
INote for OP
+solved @user1 @user2...
Cacc to me torque is zero at the point of contact of disc with surface so angular momentum can be conserved . i got L initial as mvr kcap and L final as 3/2mr^2w1 kcap where w1 is angular vel after reaching pure rolling
i finally get w/6=w1
or 2v/3 = v1
i finally get w/6=w1
or 2v/3 = v1
SFind the time at which speed of point in contact with ground is zero
Cin order to achieve pure rolling w must switch its dirn right? so here , before that happens v becomes 0 somehow after that disc starts to move backwards. i cant figure out how do we know v becomes 0
Ckind of like this
SYes
CL initial ko dekh ke how do we know this particular case happens
SAccording to me the friction will decrease the angular velocity w to w/4 at some point in time which will be equal to velocity of com and then velocity of point touching the ground would be zero
SI could be wrong im not that good at rotation
S@hardcoreisdead is this answer
Ci am not sure but i got the explanation of changing of dirns
and L initial and final are in same dirn and for pure rolling they must be in same flow. for this dirn of v must change
and L initial and final are in same dirn and for pure rolling they must be in same flow. for this dirn of v must change
Iwe good?
Cyeah
C+solved @SIMPle Potato
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November 7, 2024
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