CIRCULAR MOTION + MOMENT OF INERTIA NUMERICALS
LINKHERE- CIRCUAR MOTIONNUMERICALS1
A circular disc of mass 10 kg and radius 0.2m is set into rotation about
an axis passing through its centre and perpendicular to its plane by
applying torque 10 Nm.
Calculate angular velocity of the disc that it
will attain at the end of 6 s from the rest. (Ans.: 300 rad/s)
A solid sphere of diameter 25 cm and mass 25kg rotates about an axis
through its centre. Calculate its moment of inertia, if its angular
velocity changes from 2 rad/s to 12 rad/s in 5 second. Also calculate
the torque applied. (Ans.: I = 0.1562 kgm2 = 0.3124 Nm)
A torque of 400 Nm acting on a body of mass 40 kg produces an angular
acceleration of 20 rad/s2. Calculate the moment of inertia and radius of
gyration of the body. (Ans.: 20 kgm2, 0.707 m
If the radius of solid sphere is doubled by keeping its mass constant,
compare the moment of inertia about any diameter. (Ans.: 1:4)
(8)
A flywheel in the form of disc is rotating about an axis passing
through its centre and perpendicular to its plane looses 100J of energy,
when slowing down from 60 r.p.m. to 30 r.p.m. Find its moment of
inertia about the same axis and change in its angular momentum. (Ans.:
6.753k gm2, A L = 21./1 I— ISL2 )
Four point masses 1 kg, 2 kg, 3 kg and 4 kg are located at the corners
A, B, C and D respectively of a square ABCD of side 1 m. Find moment of
inertia and radius of gyration of the system about AB as the axis of
rotation.