A cylinder of mass 8.0 kg rolls without slipping on a horizontal surface. At a certain instant its center of mass has a speed of 15.0 m/s.
(a) Determine the translational kinetic energy of its center of
mass.
J
(b) Determine the rotational kinetic energy about its center of
mass.
J
(c) Determine its total energy.
(a)
m = mass of the cylinder = 8 kg
v = linear speed of cylinder = 15 m/s
translational kinetic energy is given as
KEtrans = (0.5) m v2
KEtrans = (0.5) (8) (15)2
KEtrans = 900 J
(b)
r = radius of the cylinder
I = moment of inertia of the cylinder = (0.5) mr2
w = angular speed
rotational kinetic energy is given as
KErot = (0.5) Iw2
KErot = (0.5) ((0.5) mr2 ) (v/r)2
KErot = (0.5) (0.5) m v2
KErot = (0.25) m v2
KErot = (0.25) (8) (15)2
KErot = 450 J
c)
total energy is given as
TE = KEtrans + KErot
TE = 900 + 450
TE = 1350 J
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