1
JEE Main 2014 (Offline)
+4
-1
A bob of mass $$m$$ attached to an inextensible string of length $$l$$ is suspended from a vertical support. The bob rotates in a horizontal circle with an angular speed $$\omega \,rad/s$$ about the vertical. About the point of suspension:
A
angular momentum is conserved
B
angular momentum changes in magnitude but not in direction.
C
angular momentum changes in direction but not in magnitude.
D
angular momentum changes both in direction and magnitude.
2
JEE Main 2014 (Offline)
+4
-1
A mass $$'m'$$ is supported by a massless string wound around a uniform hollow cylinder of mass $$m$$ and radius $$R.$$ If the string does not slip on the cylinder, with what acceleration will the mass fall or release?
A
$${{2g} \over 3}$$
B
$${{g} \over 2}$$
C
$${{5g} \over 6}$$
D
$$g$$
3
JEE Main 2013 (Offline)
+4
-1
A hoop of radius $$r$$ and mass $$m$$ rotating with an angular velocity $${\omega _0}$$ is placed on a rough horizontal surface. The initial velocity of the center of the hoop is zero. What will be the velocity of the center of the hoop when it cases to slip?
A
$${{r{\omega _0}} \over 4}$$
B
$${{r{\omega _0}} \over 3}$$
C
$${{r{\omega _0}} \over 2}$$
D
$${r{\omega _0}}$$
4
AIEEE 2011
+4
-1
A thin horizontal circular disc is rotating about a vertical axis passing through its center. An insect is at rest at a point near the rim of the disc. The insect now moves along a diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc.
A
continuously decreases
B
continuously increases
C
first increases and then decreases
D
remains unchanged
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