11.2 notes. in other words, all the kinetic energy in a system plus all the potential energy of a...
TRANSCRIPT
![Page 1: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/1.jpg)
CONSERVATION OF ENERGY
11.2 notes
![Page 2: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/2.jpg)
Mechanical Energy = K + Ug
In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the system.
![Page 3: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/3.jpg)
Example1
![Page 4: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/4.jpg)
Example 2
![Page 5: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/5.jpg)
Example 3
![Page 6: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/6.jpg)
All mechanical energy = 100%
So, if you calculate that 42% of the energy a falling object has is kinetic energy, then ________% must be potential.
![Page 7: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/7.jpg)
Part 2
All the kinetic energy plus all the potential energy before something happens equals all the kinetic energy plus all the potential energy after the event.
This is called Conservation of Energy
![Page 8: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/8.jpg)
New Formula (kinda)
Kbefore + Ugbefore = Kafter + Ugafter
![Page 9: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/9.jpg)
Otherwise known as…
1/2mv2 + mgh = 1/2mv2 + mgh
![Page 10: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/10.jpg)
Example problem 1
Tarzan, mass 85 kg, swings down on the end of a 20m vine from a tree limb 4.0 m above the ground. How fast is Tarzan moving when he reaches
the ground? Does your answer depend on Tarzan’s mass? Does your answer depend on the length of the
vine?
![Page 11: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/11.jpg)
Sketch it
![Page 12: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/12.jpg)
List the variables
m = 85 kg h = 4 m l = 20 m
![Page 13: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/13.jpg)
Other things we know…
Kinetic energy before is…Potential energy after is…
Come on, think!
![Page 14: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/14.jpg)
Kb + Ugb = Ka + Uga
0 + (85)(9.8)(4) = 1/2 (85)v2 + 0
v2 =
v =
![Page 15: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/15.jpg)
Does his speed depend on his mass?
![Page 16: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/16.jpg)
Does his speed depend on the vine’s length?
![Page 17: 11.2 notes. In other words, all the kinetic energy in a system plus all the potential energy of a system is total amount of mechanical energy in the](https://reader034.vdocuments.net/reader034/viewer/2022051516/56649cd05503460f9499c128/html5/thumbnails/17.jpg)