Chapter 19 Answer Key: Selected Topics in Astrophysics

Chapter 19: Selected Topics in Astrophysics – Key

19.1 Escape Velocity

1. vesc = 10 900 m/s or 10.9 km/s

2. vesc = 42 120 m/s or 42.1 km/s

3. vf = 9.1 km/s

4. 3.88 x 107 m above Earth’s surface

5. ∆ vesc = 10 020 m/s (≈ 20.0 km/s)19.2

19.2 The Size of Black Holes

1. Rs = 0.0089 m or 8.9 mm

2. Rs = 2953 m or 2.95 km

3. Rs = 3.54 x 1013 m (a little under 8 times Neptune’s orbit)

4. 1.35 x 1027 kg5. For the ship: 5.4 x 1010 m/s2 (≈ 5.5 billion gravities difference)

For the astronaut: 5.3 x 108 m/s2 (≈ 53 million gravities difference)

19.3 Orbital Mechanics

1. T = 2.37 x 106 s or 27.5 days

2. T = 3.16 x 107 s or 365.3 days

3. T = 5460 s or 1.52 h

4. 1.606 x 107 m (≈ 16 000 km)

5. r = 1.2 x 1011 m

19.4.1 Geosynchronous Satellites

1. d = 35 900 km above the Earth’s surface

19.4.2 Artificial Gravity in Space

1.∆ g = 0.20 m/s2 or ≈ 0.02 gs

19.4.3 Measuring the Mass of the Sun

1. ms = 1.989 x 1030 kg

19.4.4 The Most Distant World Visited – Arrokoth

1. r = 6.7 x 1012 m or 6.7 billion km