According to Newton's first law of motion, what will an doject in motion do when no extemal force acts on
come to a stop
move at the same velocity
speed up
change direction

Move at the same velocity

Explanation:

According to newton's first law also known as law of inertia: "A body at rest or in state of uniform motion will continue to be in that state unless any external force acts upon it"

Now in real life, a body will come to stop due to external forces like friction, air resistance etc but in ideal case, it will continue moving with the same velocity.

heats surface water up