Final answer:
The statement is true; a rocket escaping Earth's gravitational pull will travel in a straight line until another force acts on it, in accordance with Newton's first law of motion.
Step-by-step explanation:
The statement, "A rocket is launched into space and escapes Earth's gravitational pull. It will continue to travel in a straight line until it is acted on by another force," is true. According to Newton's first law of motion, also known as the law of inertia, an object in motion will stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force. In the vacuum of space, where there is no air resistance, a rocket that has escaped Earth's gravitational pull would indeed continue to move in the same direction at a constant speed unless other forces, such as gravity from another celestial body or resistance from interstellar matter, act upon it.