“If a man will begin with certainties, he shall end in doubts;
Flowers in Liquid Nitrogen
Energy
Show Me The Physics
Radiometer
by Don Ion
Levers give you a 'mechanical advantage'
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
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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 ...
and negative if
the force acts opposite
Work and Energy
**Scalar**
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.
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
J. L. Comstock A System of Natural Philosophy:
Principles of Mechanics
©Tony Mangiacapre., - All Rights Reserved
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