An object in the vacuum of space orbits the earth at a fixed speed in a circular orbit several
hundred miles above the earth. What can we conclude about the reaction force?
a) That there is no reaction force-the net force on the object is zero, so the reaction
force is zero too.
b) The reaction force is a force that acts on the earth directed upward toward the object.
c) There is no reaction force- there’s a net force on the object, but zero reaction force because the
object is out in space.
d) The reaction force is a normal force that acts upward from the Earth’s surface.
In this scenario, the object in space is in a circular orbit around the Earth at a fixed speed. To understand the reaction force, we need to consider Newton's third law of motion, which states that for every action, there is an equal and opposite reaction.
In this case, the object is experiencing a gravitational force pulling it towards the Earth. This force is balanced by a centripetal force that keeps it in a circular orbit. According to Newton's third law, the Earth also exerts an equal and opposite force on the object, known as the reaction force.
The correct answer is (b) - The reaction force is a force that acts on the Earth, directed upward towards the object. This force is necessary to maintain the object's circular orbit due to the gravitational attraction between the Earth and the object.