# Work, Energy & Momentum

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The flashcards below were created by user it2007 on FreezingBlue Flashcards.

1. Energy
Property of a system to do work.
2. Kinetic Energy
Definition, formula, SI units
is energy of motion.  Objects that have mass and are moving with some velocity will have K.

K=(1/2)*m*(v^2)

Joule (J) = kg*m2/s2
3. Potential Energy. Definition, formula, SI units
Object is said to have a potential energy when it has a potential to do something.

• U=mgh
• J= kg*m2/s2
4. Total Mechanical Energy
is a sum of object's potential and kinetic energies.

E=U+K
5. The first law of thermodynamics
energy is never created or destroyed.
6. Conservation of Mechanical Energy
E of the system is conserved in absence of friction.  The sum of a system's potential energy and kinetic energy will be constant.
7. Work -- definition, formula, SI units
Work is not a form of energy, but a process by which energy is transferred from one system to another.

W=F*d*cosθ

J=N*m=kg*m2/s2

• θ is an angle btw force and displacement vectors
8. how many ways are there to transfer energy from one system to another.
Work and Heat
9. Power -- definition, formula, SI units
the rate at which energy is transferred from one system to another.

P=W/t

Watt (W) = J/s
10. Work-Energy Theorem
W-E Theorem offers a direct relationship btw work done on an object by all forces and the change in its kinetic energy:

Wnet=ΔK=KEf - KEi
11. Momentum
Formula and SI Units
• Quality of objects in motion.
• p=mv
• kg*m/s
12. All objects that have momentum, also have...
Inertia -- the tendency of the objects to resist changes in their motion and momentum.
13. Impulse: Definition, Formula, SI Units
• Impulse is a change in momentum
• I=FΔt=Δp=mvf - mvi
• kg*m/s
14. Elastic Collisions
Define
Give an Example
p conserved?
KE conserved?
• Where objects don't stick together.
• E.g. Billiard balls
• p conserved:  p1i + p2i = p1f + p2f
• KE conserved: KE1i+KE2i = KE1f+KE2f
15. Inelastic Collisions
Define
Give an Example
p conserved?
KE conserved?
• Where objects don't stick together
• E.g. two cars crashing
• p conserved:  p1i + p2i = p1f + p2f
• KE not conserved: ΔKEi > ΔKEf
16. Completely Inelastic Collisions
Define
Give an Example
p conserved?
KE conserved?
• Where objects stick together
• E.g. 2 cars crashing and becoming one.
• or two molecules colliding and becoming one (covalent bond).
• p conserved:  p1i + p2i = (m1+m2)*vf
• KE not conserved: ΔKEi > ΔKEf
17. In what type of collisions is momentum conserved?
In all collisions
makes it easier to accomplish a given amount of work since the input (applied) force necessary to accomplish work is reduced.

The distance through which the reduced input force must be applied, however, is increased by the same factor.

Inclined planes, levers, and pulleys provide the benefit of mechanical advantage.
19. Center of Mass
Is a point within the object at which all the object's mass could be represented as a single particle.

X=(m1x1+m2x2+....)/(m1+m2+...)

## Card Set Information

 Author: it2007 ID: 222446 Filename: Work, Energy & Momentum Updated: 2013-06-06 16:00:02 Tags: mcat Kaplan Physics Work Energy Momentum Folders: Description: Work, Energy & Momentum Show Answers:

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