A human-operated spaceship reaches the moon in 3 days. The moon is about 386,400 km from Earth. Mars, our closest planetary neighbor, is, at its closest, about 140 times farther away from us than the moon if Mars stays in place. Assuming a very simple model of the solar system, about how long would it take that same spaceship to reach Mars?(1 point)

Responses

about 2.5 years
about 2.5 years

about 1 year
about 1 year

about 7.5 years
about 7.5 years

about 22.5 years

1 answer

To find out how long it would take the spacecraft to reach Mars, we can use the information given about the distance to the Moon and the relative distance to Mars.

  1. The distance from Earth to the Moon is about 386,400 km.

  2. Mars is about 140 times farther away than the Moon, which means the distance from Earth to Mars is approximately: \[ 386,400 , \text{km} \times 140 \approx 54,096,000 , \text{km}. \]

  3. The spaceship takes 3 days to cover the distance to the Moon. To find the speed of the spaceship, we can calculate the speed as follows:

    • Distance to the Moon: 386,400 km
    • Time taken to Moon: 3 days = 3 × 24 = 72 hours.
    • Speed = Distance / Time = \( \frac{386,400 , \text{km}}{72 , \text{hours}} \approx 5,366.67 , \text{km/h}. \)
  4. Now we'll calculate the time it would take to reach Mars using the same speed:

    • Distance to Mars: 54,096,000 km
    • Time = Distance / Speed = \( \frac{54,096,000 , \text{km}}{5,366.67 , \text{km/h}} \approx 10,100 , \text{hours}. \)
  5. To convert hours to years:

    • Number of hours in a year = 24 hours/day × 365 days/year = 8,760 hours/year.
    • Time in years = \( \frac{10,100 , \text{hours}}{8,760 , \text{hours/year}} \approx 1.15 , \text{years}. \)

So, the spaceship would take about 1 year to reach Mars.

The correct answer is about 1 year.