to overcome Earth's gravitational force to protect equipment from radiation to break through the sound barrier to avoid Earth's magnetic field
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Why do satellites and spacecraft launched from Earth need to reach a specific speed to escape Earth's surface?
Possibilities:
- to overcome Earth's gravitational force
- to protect equipment from radiation
- to break through the sound barrier
- to avoid Earth's magnetic field

to overcome Earth's gravitational force