If a 65-kilogram astronaut exerts a force with a magnitude of 50. N on a satellite that she is repairing, the magnitude of the
force that the satellite exerts on her is

The satellite will also apply the same magnitude of force ( 50 N ) but in opposite direction.

Given data:

The mass of astronaut is, m = 65 kg.

The magnitude of force exerted on the satellite is, F = 50 N.

In this problem, we will apply the Newton's Third Law of motion, which says that, "To every action, there is an equal and opposite reaction". Which means if any object (say object 1) apply some force on another object (say object 2), then the object 2 will also apply same magnitude of force on object 1, but it will be in opposite direction.

In the given problem, the satellite will also apply the same magnitude of force on Astronaut.

Which means,

F' = - F

F' = - 50 N.

Negative sign shows that the direction of force is opposite.

Thus, we can conclude that the satellite will also apply the same magnitude of force ( 50 N ) but in opposite direction.

Learn more about the Newton's Third Law here:

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50N.

The magnitude of the reaction to any force is equal to the magnitude of the first force.  (See Newton #3.)