Question

Apollo 11, the spacecraft that first landed astronauts on the moon, had a mass of 28,801 kg at takeoff.
Which is the best estimate of the mass of Apollo 11?
2 x 104 kg

Answer 1

No. 28,801 kg ≈ 2.88 × 10^4 kg, so the best simple estimate is 3 × 10^4 kg (to one significant figure). 2 × 10^4 kg (20,000 kg) is too low.