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Mechanics

Free online mechanics lesson for elementary school,  middle school and high school.
chemistry high school
 




















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Gravity

How speed and mass make kinetic energy vary

 
1) mass Influences kinetic energy

The relationship between Kinetic energy, mass and speed indicates that kinetic energy and mass are proportionals.
This proportionality implies that if the mass is doubled, its kinetic energy is doubled too.
More generally, if two objects move with the same speed the most massive one has the higher kinetic energy

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2) Speed influences kinetic energy

Kinetic energy isn't proportional to speed but to its square.
If an object ( called object number one ) owns a kinetic energy KE1, a mass m and a speed v1, 
If a second object ( called object number two ) owns a kinetic energy KE2, a mass m and a speed v2 with speed v2 twice greater than speed v1 then:

KE1 = 1 x m x v12
            2
KE2 = 1 x m x v22
            2
KE2 = 1 x m x (2 x v1 )2
            2
KE2 = 1 x m x 22 x v12
            2
KE2 = 1 x m x 4 x v12
            2
KE2 =4 x ( 1 x m x v12)
                   2
KE2 = 4 x  KE1
Kinetic energy of the second objet is four times greater than the first one.
We could do the demonstration with v2 = 3 x v1: KE2 would be nine times ( 32 ) greater than KE1
 We could also do the demonstration with v2 = 4 x v1: KE2 would be sixteen times ( 42 ) greater than KE1 etc

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