Answer:
(a) 0.0225 kg m^2
(b) 0.5 kg
Explanation:
Diameter, d = 60 cm
radius, r = 30 cm = 0.3 m
KE = 0.250 J
f = 45 rpm = 45/60 rps = 0.75 rps
(a)
Angular velocity, ω = 2 x π x f = 2 x 3.14 x 0.75 = 4.71 rad/s
[tex]KE = \frac{1}{2}I\omega ^{2}[/tex]
Where, I be the moment of inertia
0.250 = 0.5 x I x 4.71 x 4.71
I = 0.0225 kg m^2
Thus, the moment of inertia of the disc is 0.0225 kg m^2.
(b) Let m be the mass of disc.
Moment of inertia of the disc is
I = 0.5 x m x r^2
0.0225 = 0.5 x m x 0.3 x 0.3
m = 0.5 kg
Thus, the mass of the disc is 0.5 kg.
