Stopping Big Ships
Name: Matthew H.
I understand that the Titanic ship was travelling
at full speed when it noticed the iceberg in its path. How long
would it have taken for the Titanic ship to go in reverse and miss the iceberg?
When an object is moving in a straight line, it will continue to
move in that direction until and unless some force is applied to
the object to cause it to change direction. You can feel this when
you are riding in a car at a constant speed -- you do not have any
feel that you are moving (if you keep your eyes closed). But if the
driver speeds up (you feel pushed back), puts on the brakes (you
feel pushed forward), or turns (you feel pulled in the direction
opposite to the turning direction). In all these examples, your
body is feeling that tendency to keep moving in the same direction,
before the change in speed or direction was made.
Now, the heavier the object, the greater the force is that
causes it to change direction. In the case of the Titanic, the
iceberg was so heavy it would not allow the ship to change
direction, so something has to give (break) and it did.
You can experience the same effect if you jump off a chair onto
the floor. The floor does not move so your body has to absorb the
shock of having to suddenly stop. This is also why parachutes are
used when people jump out of airplanes.
It is a much more difficult problem to actually calculate how
much force and how much time is required. That depends upon the
details of the particular example. But it is more important to
understand the rules. Calculating the numbers will follow when you
learn more math, but the principles do not change.
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Update: June 2012