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an 1800 kg car travelling east at 30 m/s slows down to 10 m/s what is the work done by brakes

This was a question on my test do y’all know how to do it cuz I couldn’t figure it out

Respuesta :

Answer:

Explanation:

The work done by brake friction changes the kinetic energy,

ASSUMING the road is level and other friction is ignored.

W = KEf - KEi = ½mvf² - ½mvi² = ½m(vi² - vf²)

W = ½(1800)(30² + 10²) = 900(900 - 100) = 720000 J = 720 KJ

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