Newton's Laws

If they are wearing seat belts, the seat belts will stop them by exerting a force on them and so prevent them from getting hurt.

Newton's 1st Law of motion states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force .

Newton's first law of motion

Read about examples of Newton's firt Law here:

The behavior of all objects can be described by saying that objects tend to "keep on doing what they're doing" (unless acted upon by an unbalanced force).

Your text here

Newton's 1st law applied to the rocket lift off