In this worksheet, we will practice calculating the velocity required to escape the pull of a gravitational body given the body's mass and radius.

**Q3: **

The distance from a solar system to the centre of the Milky Way is 27 000 light years. Assume that the mass contained in the sphere of radius 27 000 light years is 100 billion solar masses, taking one solar mass as kg. What is the escape velocity for the Milky Way from the position of this solar system?

- A 250 km/s
- B 216 km/s
- C 307 km/s
- D 323 km/s
- E 348 km/s

**Q4: **

What is the speed needed to escape from the Earth-Moon system from a point on the surface of Earth? Assume there are no other bodies involved and do **not** account for the fact that Earth and the Moon are moving in their orbits. Use a value of km for the distance between the centres of the Moon and Earth, kg for Earth's mass, and kg for the Moon's mass.

- A m/s
- B m/s
- C m/s
- D m/s
- E m/s

**Q5: **

Find the escape speed of a projectile from the surface of Pluto. Use a value of kg for the mass of Pluto and km for its diameter.

- A m/s
- B m/s
- C m/s
- D m/s
- E m/s

**Q6: **

What is the Schwarzschild radius for the black hole at the centre of our galaxy if it has the mass of kg solar masses? Use kg as the value of the Sun’s mass.

- A km
- B km
- C km
- D km
- E km

**Q7: **

A planetoid has a mass of kg and a radius of 963.0 km. Find the magnitude of the escape velocity from the surface of the planetoid, considering it to be spherical.

**Q8: **

What would the Schwarzschild radius be if our Milky Way galaxy of 120 billion solar mass collapsed into a black hole? Use a value of kg for the mass of the Sun.