How far does the car travel before stopping?

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The discussion centers on calculating the stopping distance of a car with a mass of 200g, traveling at 30 m/s, under a braking force of 10,000N. The initial attempt at the solution involved calculating work but yielded an incorrect distance of 2000m instead of the expected 90m. Participants suggest using either Newton's second law (F=ma) or the work-energy principle to find the correct stopping distance. The key equations mentioned include the relationship between force, mass, acceleration, and the final and initial velocities. Clarification on the correct application of these equations is sought to resolve the discrepancy in the calculated distance.
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Homework Statement



Car: mass = 200g
Moving at 30 m/s
Braking force of 10000N.
How far does the car travel before stopping?

Homework Equations


W=m x N
w = F (delta x)


The Attempt at a Solution


I found work, (2000)(10000) = 20,000,000
Then rearranged the second equation to get delta x, and got 2000 as my answer. The answer is 90m and I'm not getting it. Any suggestions?
 
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collegegirl said:

Homework Statement



Car: mass = 200g
Moving at 30 m/s
Braking force of 10000N.
How far does the car travel before stopping?

You can go one of two routes:

(1) \vec{F}=m\vec{a} and \vec{v}_f^2=\vec{v}_i^2+2\vec{a}\Delta x, or

(2) \Delta E_k=\vec{W}, where \vec{W}=\vec{F}\Delta x.
 

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