Kinetic Energy problem i think

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Homework Help Overview

The discussion revolves around a kinetic energy problem involving the energy required to accelerate a car between different velocity ranges, specifically from 10-20 m/s and from 20-30 m/s.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants explore the relationship between kinetic energy and velocity changes, questioning how to calculate the energy required for different acceleration intervals. Some participants suggest using the conservation of energy and the work-energy principle to analyze the problem.

Discussion Status

Participants have provided calculations for kinetic energy changes and are discussing the implications of these values. There is an ongoing exploration of whether the energy required for different velocity changes is consistent with their calculations.

Contextual Notes

Participants are working under the assumption that mass is constant and have chosen a specific mass for their calculations. There is a focus on understanding the differences in energy requirements without reaching a definitive conclusion.

nlsed
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Homework Statement



What takes more energy? Accelerating a car from 10-20m/s or from 20-30m/s? Why?

Homework Equations





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

Plug in the numbers.
 
then change in kinetic energy equals the work done, which one requires more work?
 
so is this right? since m is constant it is just 1kg

1/2mv2
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 (10-20m/s) = 150 joules
KE for (20-30m/s) = 250 joules

So accelerating from 20-30m/s requires 100 more joules of energy?
 
Last edited:
nlsed said:
So accelerating from 20-30m/s requires 100 more joules of energy?

That should do it.
 
Thank you very much! :!)
 

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