1. You swing a 0.21kg penguin statue around in a horizontal
circle at the end of a 0.84m long string. The statue’s speed is
6.3 m/s. What is the magnitude of its angular momentum?

1) given
m = 0.21 kg
r = 0.84 m
v = 6.3 m/s
angular momentum, L = m*v*r
= 0.21*6.3*0.84
= 1.11 kg.m^2/s <<<<<<Answer
2) given
m = 4.1 kg
R = 0.055 m
v = 0.75 m/s
total kinetic energy = linear kinetic energy + rotational kinetic energy
= (1/2)*m*v^2 + (1/2)*I*w^2
= (1/2)*m*v^2 + (1/2)*(1/2)*m*R^2*w^2
= (1/2)*m*v^2 + (1/4)*m*(R*w)^2
= (1/2)*m*v^2 + (1/4)*m*v^2
= (3/4)*m*v^2 ( v = R*w)
= (3/4)*4.1*0.75^2
= 1.73 J <<<<<<<<Answer
3) angular momentum of the earth, L = I*w
= m*r^2*(2*pi/T)
= 5.97*10^24*(1.5*10^11)^2*(2*pi/(365*24*60*60))
= 2.68*10^40 kg.m^2/s <<<<<<<<Answer
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