If you visited a virtual Newton’s Cradle website or played with the real device, you might have noticed that after a few swings, the balls slow down. The height they reach gets shorter and shorter until they finally stop moving. If energy is transformed from one type to the other and transferred between the different balls in the device, why does the motion in Newton’s Cradle finally stop? (Hint: Think about something you decided to ignore earlier in the reading.)

the tides are influenced by both the moon and the sun, it's easy to see that when the sun lines up with the moon and the earth, as during a new moon or full moon, the tidal effect is increased. these are known as spring tides, named not for the season, but for the fact that the water "springs" higher than normal. on the other hand, if the sun and the moon are 90 degrees apart in relation to an observer on earth as during the first quarter moon or third quarter moon, then high tides are not as high as they normally would be. this is because despite its greater distance, the sun's mass allows it to exert enough gravitational force on the oceans that it can negate some of the effects of the moon's pull. this phenomenon of lower high tides is called a neap tide. if you need more information on this topic visit moonconnection.com.

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >