“If a man will begin with certainties, he shall end in doubts;
― Francis Bacon, The
Oxford Francis Bacon IV:
Energy
Show Me The Physics
Radiometer
Gasoline is a form of energy
by Don Ion
Levers give you a 'mechanical advantage'
[ Flash ]
1st gear requires a small force and a lot pedaling, while 10th gear requires little pedaling but larger force.
An Incline Plane is a Simple Machine
[ Flash ]
I) Work - when a force F acts parallel to the motion of an object over a distance d.
Work is positive when the force acts in the same direction as the object's motion ... (When the weight is lifted up)
and negative if
the force acts opposite (When the weight is brought down)
Work and Energy
**Scalar**
(means direction doesn't count) 1 + 1 always = 2
A) Equation
F - force
acting Δd - displacement Other units for work (Joule) or Kg m2/sec2
Challenge Question: Two people exert a 10 Newton force on a block for 2 meters. One person exerts her force at a 50-degree angle.
Did both people do the same work???
Person 2 does more work
Compound pulleys reduce the force
Moufle - Ilustración de un polispasto de cuatro poleas. Copyright © 2004 CR. Imagen creada para la Wikipedia en Español. (Borrar todas) (act) 09:40 7 ago 2004 (Ilustración de un polispasto de cuatro poleas.)
Machines reduce force but
a)150. J b)100. J c)200. J d)40.0 J
Ex) A
20.0-N force
is used to push a 2.00-kg cart a distance of
5.00 m.
Work done on
cart =
a)150.J b)100. J c)200.J d)40.0 J
B) Work and F vs. d diagram (plot)
W = Area Under Plot = 1/2bh
= 1/2(5 m)(3 N)
7.5 Nm
Ramps reduce the force needed to move
If W = 12 N, P could be as small as .... J. L. Comstock A System of Natural Philosophy:
Principles of Mechanics
©Tony Mangiacapre., - All Rights Reserved
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