The speed of the wave depends on the properties of the material through which it travels. When light waves travel through air and then enter water, the waves slow
down and change direction. This is called:

close lines strong magnet less close weaker

c. newton's third law of motion

the moving of the box is a result of centripetal force. think of that  as a car or a truck in this case creates a turn, the force of friction performing upon the turned wheels of the car runs centripetal force obligatory for circular motion for the things inside it.