Gigo 1249R, Manual, Page: 70 / 80

69
B
rainstorming
B
rainstorming
A Newton’s cradle is a device which consists
of five identically-sized steel balls suspended on
a metal frame. The steel balls are touching each
other at rest. This limits the movement of the steel
balls in a one-dimensional elastic collision. Therefore, if you
were to lift up the right-end ball and release it freely, it will strike
the second ball beside it. Because every steel ball’s mass is the
same, the first ball stops and transmits its energy to the second one. Now the
second ball has the same speed that the first ball had before striking. Because
the second ball touches the third ball, the same elastic collision as before
happens again. When the energy transmits to the left-end ball, the ball swings
upward. When the left-end ball strikes back, the same sequence happens
again. Only the end-balls swing. The balls in the middle stay still.
Can you feel the impact from the other side of the wall?
Daily
Application
Daily
Application
After school, Tony and his friends went to play billiards together. This was
Tony’s first time playing. After seeing his friends continuously knocking balls
into the corner pockets, Tony felt like a loser. It seemed that he couldn’t get the
technique down right.
Tony’s friend told Tony that in order to hit the a ball into one of the pockets,
you have to imagine the hit-point of the cue ball first. Then, you must predict
the trajectory of the target ball after it
gets hit by the cue ball. Basically, you
can assume a two-dimensional strike; the
striking angle and force of the cue ball will
decide the direction and distance the target
ball will travel. After their explanation, Tony
finally understood the trick behind playing
billiards.
Kids, now that you understand the
principles of elastic collision, try building a
buffer track and test it by colliding balls!
18 Buffer Track
Scientific
Application
Elastic Collision