Calculating Acceleration for a Sports Car Stopping from 90 km/h in 50 m

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Homework Help Overview

The problem involves calculating the acceleration of a sports car that stops from a speed of 90 km/h over a distance of 50 m. The subject area is kinematics, specifically focusing on motion equations related to acceleration and deceleration.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to use the kinematic equation v² = v0² + 2a(x-x0) to find acceleration but expresses uncertainty about the correctness of their result. Some participants question the sign of the acceleration and suggest verifying the result by substituting it back into the equation.

Discussion Status

The discussion is ongoing, with participants providing clarifications and suggesting methods to check the calculations. There is no explicit consensus on the correctness of the original poster's result, but guidance has been offered regarding verification of the calculations.

Contextual Notes

The original poster expresses a lack of confidence in their understanding of the problem, indicating potential difficulties with the concepts involved in kinematics.

UpperNinety08
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[SOLVED] What am I missing here?

Homework Statement



A sports car is advertised to be able to stop in a distance of 50 m from a speed of 90 km/h. What is its acceleration in m/s²?


Homework Equations



v² = v0² + 2a(x-x0)

The Attempt at a Solution



I attempted to solve for a using this equation, but came out with a value like 6 m/s² which I don't believe is correct. The first thing I did was multiply 90 km/h by .2777777 to convert it to m/s which gave me roughly 25 m/s. I plugged in 625 in for v0² (25²) and divided that by 50 m (50 - 0). I got 12.5 which after divided by 2 gave me 6.25, which like I said above I can't imagine is correct. Help :(
 
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You seem to have done everything perfectly, except perhaps the sign of the acceleration. Why do you not think think its correct?
 
I don't know I'm just really bad at this stuff. Thanks for the clarification anyway.
 
A very simple way to check is to just put the value back into the equation and see if it does what you expect. In this case you would expect the final velocity to be 0. Or in other words, both terms on the right hand side would have to be equal.
 

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