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Example: Earth's Translational Angular Momentum
Calculate the magnitude of the Earth's translational (orbital) angular momentum relative to the Sun when the Earth is at location A and when the Earth is at location B as displayed in the representation of the situation in the representations. The mass of the Earth is 6 x 1024kg and its distance from the Sun is 1.5 x 1011m.
Facts
Lacking
Approximations & Assumptions
Representations
Solution
The Earth makes one complete orbit of the Sun in 1 year, so its average speed is:
v=2π(1.5×1011m)(365)(24)(60)(60)s=3.0×104m/s
At location A
→p=⟨0,6×1024kg⋅3.0×104m/s,0⟩
→p=⟨0,1.8×1029,0⟩kg⋅m/s
∣→p∣=1.8×1029kg⋅m/s
∣→Ltrans,Sun∣=(1.5×1011m)(1.8×1029kg⋅m/s)sin90∘
∣→Ltrans,Sun∣=2.7×1040kg⋅m2/s