Newton's First Law Practice Test

Based on the scenario, a spacecraft coasts in a vacuum with engines off, and external forces are negligible, so net $F=0$. What prevents the spacecraft from spontaneously changing speed or direction?

Based on the scenario, a car moves at constant speed on a straight road where drag and rolling resistance are negligible, so net $F=0$. Why does the car continue its state of motion until braking provides a net force?