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KE1/2mv^2by truckerron1
Tags: ke1 or 2mv2 
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#1
Jan2806, 12:08 PM

P: 8

hi I am new and new to physics i am have alot of trouble with this problem
mass =1.3kg 41.5J how do i get the velocity so far i have it wrote like this 41.5J=1/2(1.3kg)(v)^2 but dont know how else to do plz help thanks ron 


#2
Jan2806, 12:26 PM

P: 483

The equation KE=1/2mv^2 says that the kinetic energy is equal to half of the mass of the object times the object's velocity squared. So you need to solve for velocity (v). Isolate the v variable using algebra (try to get v by itself on one side of the equation).



#3
Jan2806, 01:10 PM

P: 29

KE=1/2mv^2
41,5J=1/2*1,3*v^2 41,5J/(1/2*1,3)=1/2*1,3*v^2/1/2*1,3 63,8=v^2 sqrt(63,8)=v v=7,98 m/s 


#4
Jan2806, 03:24 PM

Mentor
P: 7,315

KE1/2mv^2
You will find that it is easier to do your algebra BEFORE plugging in the numbers. You have
[tex] \mbox{KE} = \frac 1 2 m v^2 [/tex] then [tex] 2 \mbox{KE} = m v^2 [/tex] then [tex] 2 \frac {\mbox{KE}} m = v^2 [/tex] so [tex] v = \sqrt { 2 \frac {\mbox{KE}} m } [/tex] Now you can substitute in your numbers and arrive at the numeric solution. 


#5
Jan2806, 03:41 PM

P: 8

thank you for the help i have been out of school 24 years and this is my last semester for my degree thanks ron



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