College

7. A satellite in a circular orbit rotates around the Earth every 120 minutes. If the Earth's radius is 4000 miles at sea level, and the satellite's orbit is 400 miles above sea level, approximately what distance does the satellite travel in 40 minutes?

A. 1400 miles
B. 9210 miles
C. 4400 miles
D. 4120 miles
E. 8000 miles

Answer :

Answer:

b.9210

Explanation:

circumference of circle = 2πr

So, the circumference of satellite's orbit = 2π(4400) = 8800π

GIVEN: the satellite in a circular orbit rotates around the Earth every 120 minutes.

In other words, the satellite travels 8800π every 120 minutes

So, in 40 minutes, the satellite will travel 1/3 of the 8800π mile orbit (since 40 minutes is 1/3 of 120 minute)

Distance traveled = 8800π/3

The satellite travels approximately 9210 miles in 40 minutes. Therefore, the correct answer should be b. 9210 miles.

To determine the distance a satellite travels in 40 minutes, we need to first calculate its orbital circumference and then its fraction traveled in 40 minutes.

The satellite orbits 400 miles above sea level, making the total orbital radius the Earth's radius plus the altitude:

  • 4000 miles + 400 miles = 4400 miles.

The orbital circumference (C) is given by:

  • C = 2πr = 2π × 4400 miles ≈ 27664 miles.

The satellite completes one orbit in 120 minutes. In 40 minutes, it will complete:

  • 40/120 = 1/3 of its orbit.

Thus, the distance traveled is:

  • (1/3) × 27664 miles ≈ 9214.67 miles.

The closest answer choice is 9210 miles (Option b).