Which body is closest to uniform movement? a) a washer sliding on smooth ice b) braking a car

Which body is closest to uniform movement? a) a washer sliding on smooth ice b) braking a car c) a train that started moving

Answer a).
The closest thing to a uniform movement will be the movement of the puck sliding on smooth ice, since only the friction force of the sliding surface of the washer on the ice hinders its uniform movement (if the puck still rotates, then the friction force will be partially compensated by various surface elements). A braking car and a train that starts moving will have sufficient acceleration so that their movement is not considered uniform (it is necessary to reduce the acceleration and braking time).