A force is changing the motion of the bus.
Newton's first law of motion states that an object at rest or uniform motion in a straight line will continue in that form unless acted upon by an external force.
The applied force on the bus in the form of brakes acts as the external force on the bus.
According to Newton's first law of motion, the external force (brakes) will change the motion of the bus.
Thus, we can conclude that a force is changing the motion of the bus.
Learn more about Newton's first law of motion here: https://brainly.com/question/24922261