How does Newton's first law affect a rocket?
1 Answer
A rocket will only travel in a straight line at a constant velocity if there are no outside, unbalanced forces acting on it.
Explanation:
Newtons first law says that an object will travel in a straight line at a constant velocity unless it is acted upon by an outside, unbalanced force.
There is a special case when the velocity is zero, then the object will remain at the same position with zero velocity unless acted upon by an outside, unbalanced force.
For a rocket, this means that if it is far from any stars or planets and has its engines off, it will travel in a straight line at a constant velocity forever.
If the engines are on, if the rocket feels the force of gravity from a planet or if there is drag from the air, the rocket will not longer have a constant speed and/or direction. This also means that if you want to slow your rocket down, you will also need to apply a force (opposite to your direction of motion).
