Physics Circular Motion Problem?
When it orbited the Moon, the Apollo 11
spacecraft’s mass was 10300 kg, its period
was 133 min, and its mean distance from the
Moon’s center was 1.99345 × 106 m. Assume
its orbit was circular and the Moon to be a
uniform sphere of mass 7.36 × 1022 kg.
Given the gravitational constant G is
6.67259 × 10−11 N m2
/kg2
, calculate the orbital speed of the spacecraft.
Answer in units of m/s.
Answers
Andrew Smith
Clearly both G and the mass of the moon are "red herrings" Speed = distance / time = 2*pi() * R / T = 2 * pi() * 1.99345* 10 ^ 6 / 133 = 94 km /min or 94 * 60 km / hr or 94/60 km/ s = 1.57 * 10 ^ 3 m/s
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