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Kinetic Energy problem... i think.. 
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#1
Mar409, 06:56 PM

P: 10

1. The problem statement, all variables and given/known data
What takes more energy? Accelerating a car from 1020m/s or from 2030m/s? Why? 2. Relevant equations 3. The attempt at a solution Since KE = 1/2mv^2, I suppose the higher the velocity is the more kinetic energy the car will have, but I have no clue how to solve this problem. 


#2
Mar409, 07:33 PM

HW Helper
P: 5,341

Won't the bigger change in kinetic energy require the greater energy?
You know that conservation of energy thing? Plug in the numbers. 


#3
Mar409, 07:36 PM

P: 473

then change in kinetic energy equals the work done, which one requires more work?



#4
Mar409, 07:40 PM

P: 10

Kinetic Energy problem... i think..
so is this right? since m is constant it is just 1kg
1/2mv^{2} 1/2(1kg)(10m/s)^{2} = 50 joules 1/2(1kg)(20m/s)^{2} = 200 joules 1/2(1kg)(30m/s)^{2} = 450 joules KE for (1020m/s) = 150 joules KE for (2030m/s) = 250 joules So accelerating from 2030m/s requires 100 more joules of energy? 


#5
Mar409, 08:15 PM

HW Helper
P: 5,341




#6
Mar409, 08:34 PM

P: 10

Thank you very much!!!



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