### Re: What is the difference between compression and tensil Streangth?

Date: Wed Apr 21 12:24:07 1999
Posted By: henryson omoregie, Faculty, engineering, boise state university
Area of science: Engineering
ID: 919616882.Eg
Message:

Question (a):	What is the difference between "Compression" and "Tensile
Strength"?

Comment:	I have to limit my explanation to your level of
understanding since you are a third grade student.

Answer (a):	When you throw a ball or land a punch on an opponent, you
are applying or using force. Force is an interesting subject but we
wouldn't get into this subject but the word 'force' will be used to explain
COMPRESSION: When you push on both sides of a spring or sleep on a
spring bed, you are applying a force that is due to compression.  On the
other hand, if you pull on both sides of the spring you applying TENSION
force.

TENSILE STRENGTH: If you pull on a spring up to the point that the
spring breaks, then the force applied to the point of failure is called
TENSILE STRENGTH. In order word, the force applied to the spring up to the
point of failure (break point) is called TENSILE STRENGTH.

Answer (b):	STRESS: Have you ever been under PRESSURE?. Engineers in
the areas of Civil, Mechanical, Chemical, and Materials, often used the
weight on a certain area of the patio contributes to the pressure your body
is exerting on the area of the patio. Now, if you press hard on the round
side of an egg and you press on the cone side of the egg using the same
force, which side will break first?. Well, the STRESS (or PRESSURE) on cone
side of the egg is going to be larger than the round (circular) side. DO
YOU AGREE WITH THIS STATEMENT?. I HOPE SO. Let's discuss this a little bit
further. Remember that STRESS is defined as FORCE DIVIDE BY AREA. Remember
the area of the cone side of the egg is approximately half the area of the
round side, therefore the STRESS required to break the cone side under
compression is twice as large as the stress required of the round side. The
round side, under compression and for the same force, will break first
before the cone side. Likewise, if you have a boiled egg which usually have
void (air space) on the round side of the egg, breaking the round side of
this boiled egg is faster that the cone side.  Why? (1) Requires minimum
stress on the round side compared to the cone side and (2) the contribution
of the air space (void) inside the boiled egg.

Answer (c):	EQUATION FOR STRESS: FORCE/AREA, that is, Force divide by
area. Force is mass multiply by gravitational constant and Area is length
multiply by width. The quantity scientists used to describe force is
pound-force ( or KILOGRAM FORCE) and for area, square feet (square meter).
Goodluck to you as a future Engineer and God Bless.

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