| word looked up : | home / archive |
LeverA lever is a rigid object that is used with an appropriate fulcrum[?] or pivot point to multiply the mechanical force that can be applied to another object.This is also termed mechanical advantage. The earliest remaining writings regarding levers are provided by Archimedes ("Give me a place to stand, and I will move the Earth.", a remark of Archimedes quoted by Pappus of Alexandria[?]) who formally stated the correct mathematical principle of levers. The force applied (at end points of the lever) is proportional to the ratio of the lever arms measured between the fulcrum and application point of the force applied at each end of the lever. Insert a better freebody diagram here when one is available. Example:
1000 lb boulder 50 lb force
applied down
|
\_____/ \|/
lllllllllllllllllllllllllllllllllllllllllllll
^
Fulcrum
The principle of the lever tells us that the above would be in static equilibrium with all forces balancing. The force applied upwards on the boulder is equal to the ratio of the lever arms times the force applied at the other end by the operator. (40/2)*50 = 1000. Increase the downward force a trifle and the boulder begins to move. By applying a fifty pound force plus a little more we can lift thousand pound boulders! A pulley assembly (see also block and tackle[?]) made of different size pulleys exploits this fundamental principle, as do gear assemblies or mechanical transmissions. The principle of leverage can also be derived using Newton's laws of motion and modern statics. Modern examples of the lever in use include: the crowbar[?], a steam shovel[?], an adjustable teeter totter[?] and the cantilever. See also engineering mechanics miser for vinegar.html">vinegar, a wise man for salt.html">salt.html">salt, and a madcap to stir the
-- SPANISH PROVERB
made by fools. "Mixing" comes by intuition, and the successful cooks
recipe.html">recipe.
Any number of salads and fillings for sandwiches for home use, teas or
following simple recipe for dressing. The secret of success of the
tablespoon even full of common mustard.html">mustard, one-half teaspoonful of salt,
thoroughly, add three tablespoonfuls of good table oil, and stir
vinegar, and stir for five minutes. Now you will have dressing
keep in a cool place for weeks.
LETTUCE SALAD.
Add to the above dressing just before serving, one pound of crisp
dish or dishes with the white.html">white.html">white.html">white of the egg, chopped fine, to which add
fourth of a lemon (with rind), two bunches of celery.html">celery, or a like amount
Serve on a lettuce leaf in individual dishes; garnish with the white
can be utilized by the judicious cook in connection with the dressing.
SANDWICH FILLING.
Take ham, veal, chicken.html">chicken, sardines, etc., with the white of the eggs,
make a paste the consistency of butter; spread this on thin slices of
sandwiches.
Dedicated to the Committee, by
H. M. STOWE.
CHICKEN SALAD. MRS. JOHN LANDON.
Take white and choice dark meat.html">meat of a cold boiled chicken or turkey,
cucumber pickles, chopped well and mixed together. For the dressing
it a teaspoonful of salt, teaspoonful pepper, teaspoonful mustard, two
last of all, one-half cup vinegar. Pour the dressing over the
much celery as you have meat. For the dressing, take six yolks and
. All is still licensed under the GNU FDL.
|
|
|||||