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(1)

Find the speed of a satellite in a circular orbit around the Earth with a radius 3.11 times the mean radius of the Earth; RE= 6.37·103 km ME= 5.98·1024 kg

(2)

A truck carrying a 29 kg crate accelerates uniformly from rest to 98 km/hr in 16.5 s. Calculate the work done on the crate by the truck (in J).

### 1 Answer

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- Eric WangLv 71 decade agoFavorite Answer
(1)設地球半徑r質量M,衛星質量m,軌道半徑R(=3.11r)

衛星所受地球重力=繞行地球向心力

GMm/R=mv/R → v=√(GM/R)=√(6.67*10^-11*5.98*10^24/(3.11*6.37*10^6))

= 4487 m /s

(2) 98 km /hr=98000/3600= 27.2 m /s

W=ΔEk=29*27.2/2= 10754 Joule

2008-02-18 12:23:17 補充：

(1)設地球半徑r質量M,衛星質量m,軌道半徑R(=3.11r)

衛星所受地球重力=繞行地球向心力

GMm/R²=mv²/R → v=√(GM/R)=√(6.67*10^-11*5.98*10^24/(3.11*6.37*10^6))

=4487 m/s

(2) 98 km/hr=98000/3600=27.2 m/s

W=ΔEk=29*27.2²/2=10754 Joule

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