Study the scenario.

as a spacecraft moves beyond pluto, its thrusters are turned on for a short time to boost its speed to approximately 32,500 mi/h. the thrusters are then turned off.

if no other forces ever act on the spacecraft what will it do?

it will continue moving in the same direction, but it will speed up because there are no forces to slow it down

it will continue moving at 32,500 mi/h the same direction because forces are not required for an object to continue its motion

it will stop immediately because a force is needed constantly for it to move at all

it will continue moving in the same direction, but it will gradually slow down because a force is needed to maintain its speed.