According to Newton’s first law of motion,if there is no net force acting on an object that is moving at a constant 30 mph speed, the object will continue to move at 30 mph.
Option a
<h3><u>Explanation:</u></h3>
"Newton's first law of motion" states that an object at a stationary position or an object moving at a constant velocity continues its state of rest or of motion unless it is acted upon by an "external unbalanced resisting force".
Since the net force acting on this object is zero; the absence of any kind of force (neither internal nor external) is observed and hence the motion at constant 30 mph velocity will continue until it is resisted.